Network Working Group                                    P. Resnick, Ed.
Request for Comments: 5322                         Qualcomm Incorporated
Obsoletes: 2822                                             October 2008
Updates: 4021
Category: Standards Track

Internet Message Format


Status of This Memo


This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

このドキュメントは、インターネットコミュニティのインターネット標準トラックプロトコルを指定し、改善のための議論と提案を要求します。このプロトコルの標準化状態とステータスについては、「インターネット公式プロトコル標準」(STD 1)の最新版を参照してください。このメモの配布は無制限です。



This document specifies the Internet Message Format (IMF), a syntax for text messages that are sent between computer users, within the framework of "electronic mail" messages. This specification is a revision of Request For Comments (RFC) 2822, which itself superseded Request For Comments (RFC) 822, "Standard for the Format of ARPA Internet Text Messages", updating it to reflect current practice and incorporating incremental changes that were specified in other RFCs.

このドキュメントでは、「電子メール」メッセージのフレームワーク内で、コンピュータユーザー間で送信されるテキストメッセージの構文であるインターネットメッセージフォーマット(IMF)を指定します。この仕様は、Request For Comments(RFC)2822の改訂版であり、Request For Comments(RFC)822の「ARPAインターネットテキストメッセージのフォーマットの標準」に取って代わり、現在の慣行を反映するように更新し、指定された増分変更を組み込んでいます。他のRFCで。

Table of Contents


   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Scope  . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.2.  Notational Conventions . . . . . . . . . . . . . . . . . .  5
       1.2.1.  Requirements Notation  . . . . . . . . . . . . . . . .  5
       1.2.2.  Syntactic Notation . . . . . . . . . . . . . . . . . .  5
       1.2.3.  Structure of This Document . . . . . . . . . . . . . .  5
   2.  Lexical Analysis of Messages . . . . . . . . . . . . . . . . .  6
     2.1.  General Description  . . . . . . . . . . . . . . . . . . .  6
       2.1.1.  Line Length Limits . . . . . . . . . . . . . . . . . .  7
     2.2.  Header Fields  . . . . . . . . . . . . . . . . . . . . . .  8
       2.2.1.  Unstructured Header Field Bodies . . . . . . . . . . .  8
       2.2.2.  Structured Header Field Bodies . . . . . . . . . . . .  8
       2.2.3.  Long Header Fields . . . . . . . . . . . . . . . . . .  8
     2.3.  Body . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
   3.  Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     3.1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . 10
     3.2.  Lexical Tokens . . . . . . . . . . . . . . . . . . . . . . 10
       3.2.1.  Quoted characters  . . . . . . . . . . . . . . . . . . 10
       3.2.2.  Folding White Space and Comments . . . . . . . . . . . 11
       3.2.3.  Atom . . . . . . . . . . . . . . . . . . . . . . . . . 12
       3.2.4.  Quoted Strings . . . . . . . . . . . . . . . . . . . . 13
       3.2.5.  Miscellaneous Tokens . . . . . . . . . . . . . . . . . 14
     3.3.  Date and Time Specification  . . . . . . . . . . . . . . . 14
     3.4.  Address Specification  . . . . . . . . . . . . . . . . . . 16
       3.4.1.  Addr-Spec Specification  . . . . . . . . . . . . . . . 17
     3.5.  Overall Message Syntax . . . . . . . . . . . . . . . . . . 18
     3.6.  Field Definitions  . . . . . . . . . . . . . . . . . . . . 19
       3.6.1.  The Origination Date Field . . . . . . . . . . . . . . 22
       3.6.2.  Originator Fields  . . . . . . . . . . . . . . . . . . 22
       3.6.3.  Destination Address Fields . . . . . . . . . . . . . . 23
       3.6.4.  Identification Fields  . . . . . . . . . . . . . . . . 25
       3.6.5.  Informational Fields . . . . . . . . . . . . . . . . . 27
       3.6.6.  Resent Fields  . . . . . . . . . . . . . . . . . . . . 28
       3.6.7.  Trace Fields . . . . . . . . . . . . . . . . . . . . . 30
       3.6.8.  Optional Fields  . . . . . . . . . . . . . . . . . . . 30
   4.  Obsolete Syntax  . . . . . . . . . . . . . . . . . . . . . . . 31
     4.1.  Miscellaneous Obsolete Tokens  . . . . . . . . . . . . . . 32
     4.2.  Obsolete Folding White Space . . . . . . . . . . . . . . . 33
     4.3.  Obsolete Date and Time . . . . . . . . . . . . . . . . . . 33
     4.4.  Obsolete Addressing  . . . . . . . . . . . . . . . . . . . 35
     4.5.  Obsolete Header Fields . . . . . . . . . . . . . . . . . . 35
       4.5.1.  Obsolete Origination Date Field  . . . . . . . . . . . 36
       4.5.2.  Obsolete Originator Fields . . . . . . . . . . . . . . 36
       4.5.3.  Obsolete Destination Address Fields  . . . . . . . . . 37
       4.5.4.  Obsolete Identification Fields . . . . . . . . . . . . 37
       4.5.5.  Obsolete Informational Fields  . . . . . . . . . . . . 37
       4.5.6.  Obsolete Resent Fields . . . . . . . . . . . . . . . . 38
       4.5.7.  Obsolete Trace Fields  . . . . . . . . . . . . . . . . 38
       4.5.8.  Obsolete optional fields . . . . . . . . . . . . . . . 38
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 38
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 39
   Appendix A.     Example Messages . . . . . . . . . . . . . . . . . 43
   Appendix A.1.   Addressing Examples  . . . . . . . . . . . . . . . 44
   Appendix A.1.1. A Message from One Person to Another with
                   Simple Addressing  . . . . . . . . . . . . . . . . 44
   Appendix A.1.2. Different Types of Mailboxes . . . . . . . . . . . 45
   Appendix A.1.3. Group Addresses  . . . . . . . . . . . . . . . . . 45
   Appendix A.2.   Reply Messages . . . . . . . . . . . . . . . . . . 46
   Appendix A.3.   Resent Messages  . . . . . . . . . . . . . . . . . 47
   Appendix A.4.   Messages with Trace Fields . . . . . . . . . . . . 48
   Appendix A.5.   White Space, Comments, and Other Oddities  . . . . 49
   Appendix A.6.   Obsoleted Forms  . . . . . . . . . . . . . . . . . 50
   Appendix A.6.1. Obsolete Addressing  . . . . . . . . . . . . . . . 50
   Appendix A.6.2. Obsolete Dates . . . . . . . . . . . . . . . . . . 50
   Appendix A.6.3. Obsolete White Space and Comments  . . . . . . . . 51
   Appendix B.     Differences from Earlier Specifications  . . . . . 52
   Appendix C.     Acknowledgements . . . . . . . . . . . . . . . . . 53
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 55
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 55
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 55
1. Introduction
1. はじめに
1.1. Scope
1.1. 範囲

This document specifies the Internet Message Format (IMF), a syntax for text messages that are sent between computer users, within the framework of "electronic mail" messages. This specification is an update to [RFC2822], which itself superseded [RFC0822], updating it to reflect current practice and incorporating incremental changes that were specified in other RFCs such as [RFC1123].


This document specifies a syntax only for text messages. In particular, it makes no provision for the transmission of images, audio, or other sorts of structured data in electronic mail messages. There are several extensions published, such as the MIME document series ([RFC2045], [RFC2046], [RFC2049]), which describe mechanisms for the transmission of such data through electronic mail, either by extending the syntax provided here or by structuring such messages to conform to this syntax. Those mechanisms are outside of the scope of this specification.

このドキュメントでは、テキストメッセージのみの構文を指定します。特に、画像、音声、またはその他の種類の構造化データを電子メールメッセージで送信するための規定はありません。 MIMEドキュメントシリーズ([RFC2045]、[RFC2046]、[RFC2049])など、いくつかの拡張機能が公開されています。これらは、ここで提供される構文を拡張するか、そのような構造化によって、電子メールを介してそのようなデータを送信するメカニズムを記述します。この構文に準拠するメッセージ。これらのメカニズムは、この仕様の範囲外です。

In the context of electronic mail, messages are viewed as having an envelope and contents. The envelope contains whatever information is needed to accomplish transmission and delivery. (See [RFC5321] for a discussion of the envelope.) The contents comprise the object to be delivered to the recipient. This specification applies only to the format and some of the semantics of message contents. It contains no specification of the information in the envelope.

電子メールのコンテキストでは、メッセージは封筒と内容を持つものと見なされます。エンベロープには、送信と配信を実行するために必要なすべての情報が含まれています。 (エンベロープの説明については、[RFC5321]を参照してください。)内容は、受信者に配信されるオブジェクトを構成します。この仕様は、メッセージの内容の形式とセマンティクスの一部にのみ適用されます。エンベロープ内の情報の仕様は含まれていません。

However, some message systems may use information from the contents to create the envelope. It is intended that this specification facilitate the acquisition of such information by programs.


This specification is intended as a definition of what message content format is to be passed between systems. Though some message systems locally store messages in this format (which eliminates the need for translation between formats) and others use formats that differ from the one specified in this specification, local storage is outside of the scope of this specification.


Note: This specification is not intended to dictate the internal formats used by sites, the specific message system features that they are expected to support, or any of the characteristics of user interface programs that create or read messages. In addition, this document does not specify an encoding of the characters for either transport or storage; that is, it does not specify the number of bits used or how those bits are specifically transferred over the wire or stored on disk.


1.2. Notational Conventions
1.2. 表記規則
1.2.1. Requirements Notation
1.2.1. 要件表記

This document occasionally uses terms that appear in capital letters. When the terms "MUST", "SHOULD", "RECOMMENDED", "MUST NOT", "SHOULD NOT", and "MAY" appear capitalized, they are being used to indicate particular requirements of this specification. A discussion of the meanings of these terms appears in [RFC2119].

このドキュメントでは、大文字で表示される用語を使用することがあります。 「MUST」、「SHOULD」、「RECOMMENDED」、「MUST NOT」、「SHOULD NOT」、および「MAY」という用語は、大文字で表記されている場合、この仕様の特定の要件を示すために使用されています。これらの用語の意味の議論は[RFC2119]にあります。

1.2.2. Syntactic Notation
1.2.2. 構文表記

This specification uses the Augmented Backus-Naur Form (ABNF) [RFC5234] notation for the formal definitions of the syntax of messages. Characters will be specified either by a decimal value (e.g., the value %d65 for uppercase A and %d97 for lowercase A) or by a case-insensitive literal value enclosed in quotation marks (e.g., "A" for either uppercase or lowercase A).

この仕様では、メッセージの構文の正式な定義にAugmented Backus-Naur Form(ABNF)[RFC5234]表記を使用しています。文字は、10進数の値(たとえば、大文字のAの場合は値%d65、小文字のAの場合は%d97)、または引用符で囲まれた大文字と小文字を区別しないリテラル値(たとえば、大文字または小文字のAの「A」)で指定されます。 )。

1.2.3. Structure of This Document
1.2.3. このドキュメントの構造

This document is divided into several sections.


This section, section 1, is a short introduction to the document.


Section 2 lays out the general description of a message and its constituent parts. This is an overview to help the reader understand some of the general principles used in the later portions of this document. Any examples in this section MUST NOT be taken as specification of the formal syntax of any part of a message.


Section 3 specifies formal ABNF rules for the structure of each part of a message (the syntax) and describes the relationship between those parts and their meaning in the context of a message (the semantics). That is, it lays out the actual rules for the structure of each part of a message (the syntax) as well as a description of the parts and instructions for their interpretation (the semantics). This includes analysis of the syntax and semantics of subparts of messages that have specific structure. The syntax included in section 3 represents messages as they MUST be created. There are also notes in section 3 to indicate if any of the options specified in the syntax SHOULD be used over any of the others.


Both sections 2 and 3 describe messages that are legal to generate for purposes of this specification.


Section 4 of this document specifies an "obsolete" syntax. There are references in section 3 to these obsolete syntactic elements. The rules of the obsolete syntax are elements that have appeared in earlier versions of this specification or have previously been widely used in Internet messages. As such, these elements MUST be interpreted by parsers of messages in order to be conformant to this specification. However, since items in this syntax have been determined to be non-interoperable or to cause significant problems for recipients of messages, they MUST NOT be generated by creators of conformant messages.


Section 5 details security considerations to take into account when implementing this specification.


Appendix A lists examples of different sorts of messages. These examples are not exhaustive of the types of messages that appear on the Internet, but give a broad overview of certain syntactic forms.


Appendix B lists the differences between this specification and earlier specifications for Internet messages.


Appendix C contains acknowledgements.


2. Lexical Analysis of Messages
2. メッセージの語彙分析
2.1. General Description
2.1. 概要

At the most basic level, a message is a series of characters. A message that is conformant with this specification is composed of characters with values in the range of 1 through 127 and interpreted as US-ASCII [ANSI.X3-4.1986] characters. For brevity, this document sometimes refers to this range of characters as simply "US-ASCII characters".

最も基本的なレベルでは、メッセージは一連の文字です。この仕様に準拠するメッセージは、1〜127の範囲の値を持つ文字で構成され、US-ASCII [ANSI.X3-4.1986]文字として解釈されます。簡潔にするために、このドキュメントでは、この範囲の文字を単に「US-ASCII文字」と呼ぶ場合があります。

Note: This document specifies that messages are made up of characters in the US-ASCII range of 1 through 127. There are other documents, specifically the MIME document series ([RFC2045], [RFC2046], [RFC2047], [RFC2049], [RFC4288], [RFC4289]), that extend this specification to allow for values outside of that range. Discussion of those mechanisms is not within the scope of this specification.

注:このドキュメントでは、メッセージがUS-ASCIIの1から127の範囲の文字で構成されることを指定しています。他のドキュメント、特にMIMEドキュメントシリーズ([RFC2045]、[RFC2046]、[RFC2047]、[RFC2049]、 [RFC4288]、[RFC4289])、この仕様を拡張して、その範囲外の値を許可します。これらのメカニズムの説明は、この仕様の範囲外です。

Messages are divided into lines of characters. A line is a series of characters that is delimited with the two characters carriage-return and line-feed; that is, the carriage return (CR) character (ASCII value 13) followed immediately by the line feed (LF) character (ASCII value 10). (The carriage return/line feed pair is usually written in this document as "CRLF".) A message consists of header fields (collectively called "the header section of the message") followed, optionally, by a body. The header section is a sequence of lines of characters with special syntax as defined in this specification. The body is simply a sequence of characters that follows the header section and is separated from the header section by an empty line (i.e., a line with nothing preceding the CRLF).

メッセージは文字の行に分割されます。行とは、キャリッジリターンとラインフィードの2文字で区切られた一連の文字です。つまり、復帰(CR)文字(ASCII値13)の直後に改行(LF)文字(ASCII値10)が続きます。 (キャリッジリターンとラインフィードのペアは通常、このドキュメントでは "CRLF"として記述されています。)メッセージは、ヘッダーフィールド(まとめて "メッセージのヘッダーセクション"と呼ばれます)と、オプションで本文が続くフィールドで構成されます。ヘッダーセクションは、この仕様で定義されている特別な構文を持つ一連の文字行です。本文は、ヘッダーセクションに続く一連の文字であり、ヘッダー行と空の行(CRLFの前に何もない行)で区切られています。

Note: Common parlance and earlier versions of this specification use the term "header" to either refer to the entire header section or to refer to an individual header field. To avoid ambiguity, this document does not use the terms "header" or "headers" in isolation, but instead always uses "header field" to refer to the individual field and "header section" to refer to the entire collection.


2.1.1. Line Length Limits
2.1.1. 行の長さの制限

There are two limits that this specification places on the number of characters in a line. Each line of characters MUST be no more than 998 characters, and SHOULD be no more than 78 characters, excluding the CRLF.


The 998 character limit is due to limitations in many implementations that send, receive, or store IMF messages which simply cannot handle more than 998 characters on a line. Receiving implementations would do well to handle an arbitrarily large number of characters in a line for robustness sake. However, there are so many implementations that (in compliance with the transport requirements of [RFC5321]) do not accept messages containing more than 1000 characters including the CR and LF per line, it is important for implementations not to create such messages.


The more conservative 78 character recommendation is to accommodate the many implementations of user interfaces that display these messages which may truncate, or disastrously wrap, the display of more than 78 characters per line, in spite of the fact that such implementations are non-conformant to the intent of this specification (and that of [RFC5321] if they actually cause information to be lost). Again, even though this limitation is put on messages, it is incumbent upon implementations that display messages to handle an arbitrarily large number of characters in a line (certainly at least up to the 998 character limit) for the sake of robustness.


2.2. Header Fields
2.2. ヘッダーフィールド

Header fields are lines beginning with a field name, followed by a colon (":"), followed by a field body, and terminated by CRLF. A field name MUST be composed of printable US-ASCII characters (i.e., characters that have values between 33 and 126, inclusive), except colon. A field body may be composed of printable US-ASCII characters as well as the space (SP, ASCII value 32) and horizontal tab (HTAB, ASCII value 9) characters (together known as the white space characters, WSP). A field body MUST NOT include CR and LF except when used in "folding" and "unfolding", as described in section 2.2.3. All field bodies MUST conform to the syntax described in sections 3 and 4 of this specification.

ヘッダーフィールドは、フィールド名で始まり、その後にコロン( ":")、フィールド本文が続き、CRLFで終わる行です。フィールド名は、コロンを除いて、印刷可能なUS-ASCII文字(つまり、33〜126の値を持つ文字)で構成する必要があります。フィールド本体は、印刷可能なUS-ASCII文字、スペース(SP、ASCII値32)および水平タブ(HTAB、ASCII値9)文字(まとめてホワイトスペース文字、WSP)で構成されます。セクション2.2.3で説明されているように、「折りたたみ」と「展開」で使用する場合を除き、フィールド本体にCRとLFを含めることはできません。すべてのフィールド本体は、この仕様のセクション3および4で説明されている構文に準拠する必要があります。

2.2.1. Unstructured Header Field Bodies
2.2.1. 非構造化ヘッダーフィールド本体

Some field bodies in this specification are defined simply as "unstructured" (which is specified in section 3.2.5 as any printable US-ASCII characters plus white space characters) with no further restrictions. These are referred to as unstructured field bodies. Semantically, unstructured field bodies are simply to be treated as a single line of characters with no further processing (except for "folding" and "unfolding" as described in section 2.2.3).


2.2.2. Structured Header Field Bodies
2.2.2. 構造化ヘッダーフィールド本体

Some field bodies in this specification have a syntax that is more restrictive than the unstructured field bodies described above. These are referred to as "structured" field bodies. Structured field bodies are sequences of specific lexical tokens as described in sections 3 and 4 of this specification. Many of these tokens are allowed (according to their syntax) to be introduced or end with comments (as described in section 3.2.2) as well as the white space characters, and those white space characters are subject to "folding" and "unfolding" as described in section 2.2.3. Semantic analysis of structured field bodies is given along with their syntax.


2.2.3. Long Header Fields
2.2.3. 長いヘッダーフィールド

Each header field is logically a single line of characters comprising the field name, the colon, and the field body. For convenience however, and to deal with the 998/78 character limitations per line, the field body portion of a header field can be split into a multiple-line representation; this is called "folding". The general rule is that wherever this specification allows for folding white space (not simply WSP characters), a CRLF may be inserted before any WSP.


For example, the header field:


Subject: This is a test


can be represented as:


Subject: This is a test


Note: Though structured field bodies are defined in such a way that folding can take place between many of the lexical tokens (and even within some of the lexical tokens), folding SHOULD be limited to placing the CRLF at higher-level syntactic breaks. For instance, if a field body is defined as comma-separated values, it is recommended that folding occur after the comma separating the structured items in preference to other places where the field could be folded, even if it is allowed elsewhere.


The process of moving from this folded multiple-line representation of a header field to its single line representation is called "unfolding". Unfolding is accomplished by simply removing any CRLF that is immediately followed by WSP. Each header field should be treated in its unfolded form for further syntactic and semantic evaluation. An unfolded header field has no length restriction and therefore may be indeterminately long.


2.3. Body
2.3. 体

The body of a message is simply lines of US-ASCII characters. The only two limitations on the body are as follows:


o CR and LF MUST only occur together as CRLF; they MUST NOT appear independently in the body. o Lines of characters in the body MUST be limited to 998 characters, and SHOULD be limited to 78 characters, excluding the CRLF.

o CRとLFは、CRLFとして一緒にのみ発生する必要があります。それらはボディに独立して現れてはいけません。 o本文の文字行は998文字に制限する必要があり、CRLFを除いて78文字に制限する必要があります(SHOULD)。

Note: As was stated earlier, there are other documents, specifically the MIME documents ([RFC2045], [RFC2046], [RFC2049], [RFC4288], [RFC4289]), that extend (and limit) this specification to allow for different sorts of message bodies. Again, these mechanisms are beyond the scope of this document.


3. Syntax
3. 構文
3.1. Introduction
3.1. はじめに

The syntax as given in this section defines the legal syntax of Internet messages. Messages that are conformant to this specification MUST conform to the syntax in this section. If there are options in this section where one option SHOULD be generated, that is indicated either in the prose or in a comment next to the syntax.


For the defined expressions, a short description of the syntax and use is given, followed by the syntax in ABNF, followed by a semantic analysis. The following primitive tokens that are used but otherwise unspecified are taken from the "Core Rules" of [RFC5234], Appendix B.1: CR, LF, CRLF, HTAB, SP, WSP, DQUOTE, DIGIT, ALPHA, and VCHAR.


In some of the definitions, there will be non-terminals whose names start with "obs-". These "obs-" elements refer to tokens defined in the obsolete syntax in section 4. In all cases, these productions are to be ignored for the purposes of generating legal Internet messages and MUST NOT be used as part of such a message. However, when interpreting messages, these tokens MUST be honored as part of the legal syntax. In this sense, section 3 defines a grammar for the generation of messages, with "obs-" elements that are to be ignored, while section 4 adds grammar for the interpretation of messages.

一部の定義では、名前が「obs-」で始まる非端末があります。これらの "obs-"要素は、セクション4で廃止された構文で定義されたトークンを参照します。すべての場合において、これらのプロダクションは正当なインターネットメッセージを生成する目的で無視され、そのようなメッセージの一部として使用してはなりません。ただし、メッセージを解釈するときは、これらのトークンを有効な構文の一部として尊重する必要があります。この意味で、セクション3ではメッセージ生成の文法を定義し、「obs-」要素を無視します。セクション4では、メッセージの解釈のための文法を追加します。

3.2. Lexical Tokens
3.2. 字句トークン

The following rules are used to define an underlying lexical analyzer, which feeds tokens to the higher-level parsers. This section defines the tokens used in structured header field bodies.


Note: Readers of this specification need to pay special attention to how these lexical tokens are used in both the lower-level and higher-level syntax later in the document. Particularly, the white space tokens and the comment tokens defined in section 3.2.2 get used in the lower-level tokens defined here, and those lower-level tokens are in turn used as parts of the higher-level tokens defined later. Therefore, white space and comments may be allowed in the higher-level tokens even though they may not explicitly appear in a particular definition.


3.2.1. Quoted characters
3.2.1. 引用文字

Some characters are reserved for special interpretation, such as delimiting lexical tokens. To permit use of these characters as uninterpreted data, a quoting mechanism is provided.


   quoted-pair     =   ("\" (VCHAR / WSP)) / obs-qp

Where any quoted-pair appears, it is to be interpreted as the character alone. That is to say, the "\" character that appears as part of a quoted-pair is semantically "invisible".


Note: The "\" character may appear in a message where it is not part of a quoted-pair. A "\" character that does not appear in a quoted-pair is not semantically invisible. The only places in this specification where quoted-pair currently appears are ccontent, qcontent, and in obs-dtext in section 4.


3.2.2. Folding White Space and Comments
3.2.2. 折りたたみ空白とコメント

White space characters, including white space used in folding (described in section 2.2.3), may appear between many elements in header field bodies. Also, strings of characters that are treated as comments may be included in structured field bodies as characters enclosed in parentheses. The following defines the folding white space (FWS) and comment constructs.


Strings of characters enclosed in parentheses are considered comments so long as they do not appear within a "quoted-string", as defined in section 3.2.4. Comments may nest.


There are several places in this specification where comments and FWS may be freely inserted. To accommodate that syntax, an additional token for "CFWS" is defined for places where comments and/or FWS can occur. However, where CFWS occurs in this specification, it MUST NOT be inserted in such a way that any line of a folded header field is made up entirely of WSP characters and nothing else.


   FWS             =   ([*WSP CRLF] 1*WSP) /  obs-FWS
                                          ; Folding white space
   ctext           =   %d33-39 /          ; Printable US-ASCII
                       %d42-91 /          ;  characters not including
                       %d93-126 /         ;  "(", ")", or "\"
   ccontent        =   ctext / quoted-pair / comment
   comment         =   "(" *([FWS] ccontent) [FWS] ")"

CFWS = (1*([FWS] comment) [FWS]) / FWS Throughout this specification, where FWS (the folding white space token) appears, it indicates a place where folding, as discussed in section 2.2.3, may take place. Wherever folding appears in a message (that is, a header field body containing a CRLF followed by any WSP), unfolding (removal of the CRLF) is performed before any further semantic analysis is performed on that header field according to this specification. That is to say, any CRLF that appears in FWS is semantically "invisible".

CFWS =(1 *([FWS]コメント)[FWS])/ FWSこの仕様全体を通じて、FWS(折りたたみ空白トークン)は、セクション2.2.3で説明したように折りたたみが行われる可能性がある場所を示します。メッセージ(つまり、CRLFとその後に続くWSPを含むヘッダーフィールド本文)に折りたたみが表示される場合は常に、この仕様に従ってそのヘッダーフィールドに対してさらなる意味分析が実行される前に、展開(CRLFの削除)が実行されます。つまり、FWSに表示されるCRLFは、意味的には「見えない」ものです。

A comment is normally used in a structured field body to provide some human-readable informational text. Since a comment is allowed to contain FWS, folding is permitted within the comment. Also note that since quoted-pair is allowed in a comment, the parentheses and backslash characters may appear in a comment, so long as they appear as a quoted-pair. Semantically, the enclosing parentheses are not part of the comment; the comment is what is contained between the two parentheses. As stated earlier, the "\" in any quoted-pair and the CRLF in any FWS that appears within the comment are semantically "invisible" and therefore not part of the comment either.


Runs of FWS, comment, or CFWS that occur between lexical tokens in a structured header field are semantically interpreted as a single space character.


3.2.3. Atom
3.2.3. 原子

Several productions in structured header field bodies are simply strings of certain basic characters. Such productions are called atoms.


Some of the structured header field bodies also allow the period character (".", ASCII value 46) within runs of atext. An additional "dot-atom" token is defined for those purposes.

一部の構造化ヘッダーフィールドの本文では、テキストの実行内でピリオド文字( "。"、ASCII値46)も使用できます。これらの目的のために、追加の「ドットアトム」トークンが定義されています。

Note: The "specials" token does not appear anywhere else in this specification. It is simply the visible (i.e., non-control, non-white space) characters that do not appear in atext. It is provided only because it is useful for implementers who use tools that lexically analyze messages. Each of the characters in specials can be used to indicate a tokenization point in lexical analysis.

注:「specials」トークンは、この仕様の他の場所にはありません。テキストに表示されないのは、単に表示されている(つまり、コントロールや空白以外の)文字です。これは、レキシカルにメッセージを分析するツールを使用する実装者に役立つためにのみ提供されています。 specialsの各文字は、字句解析のトークン化ポイントを示すために使用できます。

   atext           =   ALPHA / DIGIT /    ; Printable US-ASCII
                       "!" / "#" /        ;  characters not including
                       "$" / "%" /        ;  specials.  Used for atoms.
                       "&" / "'" /
                       "*" / "+" /
                       "-" / "/" /
                       "=" / "?" /
                       "^" / "_" /
                       "`" / "{" /
                       "|" / "}" /

atom = [CFWS] 1*atext [CFWS]

アトム= [CFWS] 1 * atext [CFWS]

   dot-atom-text   =   1*atext *("." 1*atext)

dot-atom = [CFWS] dot-atom-text [CFWS]

dot-atom = [CFWS] dot-atom-text [CFWS]

   specials        =   "(" / ")" /        ; Special characters that do
                       "<" / ">" /        ;  not appear in atext
                       "[" / "]" /
                       ":" / ";" /
                       "@" / "\" /
                       "," / "." /

Both atom and dot-atom are interpreted as a single unit, comprising the string of characters that make it up. Semantically, the optional comments and FWS surrounding the rest of the characters are not part of the atom; the atom is only the run of atext characters in an atom, or the atext and "." characters in a dot-atom.

アトムとドットアトムの両方が単一のユニットとして解釈され、それを構成する文字列で構成されます。意味的には、オプションのコメントと残りの文字を囲むFWSはアトムの一部ではありません。アトムは、アトム内の一連のatext文字、またはatextと "。"のみです。ドットアトム内の文字。

3.2.4. Quoted Strings
3.2.4. 引用文字列

Strings of characters that include characters other than those allowed in atoms can be represented in a quoted string format, where the characters are surrounded by quote (DQUOTE, ASCII value 34) characters.


   qtext           =   %d33 /             ; Printable US-ASCII
                       %d35-91 /          ;  characters not including
                       %d93-126 /         ;  "\" or the quote character

qcontent = qtext / quoted-pair

qcontent = qtext /引用ペア

quoted-string = [CFWS] DQUOTE *([FWS] qcontent) [FWS] DQUOTE [CFWS]

quoted-string = [CFWS] DQUOTE *([FWS] qcontent)[FWS] DQUOTE [CFWS]

A quoted-string is treated as a unit. That is, quoted-string is identical to atom, semantically. Since a quoted-string is allowed to contain FWS, folding is permitted. Also note that since quoted-pair is allowed in a quoted-string, the quote and backslash characters may appear in a quoted-string so long as they appear as a quoted-pair.

引用文字列は1つの単位として扱われます。つまり、quoted-stringは意味的にはatomと同じです。 quoted-stringにはFWSを含めることができるため、折りたたみが許可されます。また、引用符付きペアは引用符付き文字列で使用できるため、引用符とバックスラッシュ文字は、引用符付きペアとして表示される限り、引用符付き文字列に表示される可能性があります。

Semantically, neither the optional CFWS outside of the quote characters nor the quote characters themselves are part of the quoted-string; the quoted-string is what is contained between the two quote characters. As stated earlier, the "\" in any quoted-pair and the CRLF in any FWS/CFWS that appears within the quoted-string are semantically "invisible" and therefore not part of the quoted-string either.

意味的には、引用文字の外側のオプションのCFWSも引用文字自体もquoted-stringの一部ではありません。 quoted-stringは、2つの引用文字の間に含まれるものです。前述のように、引用符付きペア内の「\」と、引用符付き文字列内に表示されるFWS / CFWS内のCRLFは、意味的に「見えない」ため、引用符付き文字列の一部でもありません。

3.2.5. Miscellaneous Tokens
3.2.5. その他のトークン

Three additional tokens are defined: word and phrase for combinations of atoms and/or quoted-strings, and unstructured for use in unstructured header fields and in some places within structured header fields.


word = atom / quoted-string


   phrase          =   1*word / obs-phrase
   unstructured    =   (*([FWS] VCHAR) *WSP) / obs-unstruct
3.3. Date and Time Specification
3.3. 日付と時刻の仕様

Date and time values occur in several header fields. This section specifies the syntax for a full date and time specification. Though folding white space is permitted throughout the date-time specification, it is RECOMMENDED that a single space be used in each place that FWS appears (whether it is required or optional); some older implementations will not interpret longer sequences of folding white space correctly.


date-time = [ day-of-week "," ] date time [CFWS]

日時= [曜日 "、"]日時[CFWS]

day-of-week = ([FWS] day-name) / obs-day-of-week

曜日=([FWS]曜日名)/ obs-day-of-week

   day-name        =   "Mon" / "Tue" / "Wed" / "Thu" /
                       "Fri" / "Sat" / "Sun"

date = day month year


   day             =   ([FWS] 1*2DIGIT FWS) / obs-day
   month           =   "Jan" / "Feb" / "Mar" / "Apr" /
                       "May" / "Jun" / "Jul" / "Aug" /
                       "Sep" / "Oct" / "Nov" / "Dec"
   year            =   (FWS 4*DIGIT FWS) / obs-year

time = time-of-day zone


   time-of-day     =   hour ":" minute [ ":" second ]

hour = 2DIGIT / obs-hour

時間= 2DIGIT / obs-hour

minute = 2DIGIT / obs-minute

分= 2DIGIT / obs-minute

second = 2DIGIT / obs-second

秒= 2DIGIT / obs-second

   zone            =   (FWS ( "+" / "-" ) 4DIGIT) / obs-zone

The day is the numeric day of the month. The year is any numeric year 1900 or later.


The time-of-day specifies the number of hours, minutes, and optionally seconds since midnight of the date indicated.


The date and time-of-day SHOULD express local time.


The zone specifies the offset from Coordinated Universal Time (UTC, formerly referred to as "Greenwich Mean Time") that the date and time-of-day represent. The "+" or "-" indicates whether the time-of-day is ahead of (i.e., east of) or behind (i.e., west of) Universal Time. The first two digits indicate the number of hours difference from Universal Time, and the last two digits indicate the number of additional minutes difference from Universal Time. (Hence, +hhmm means +(hh * 60 + mm) minutes, and -hhmm means -(hh * 60 + mm) minutes). The form "+0000" SHOULD be used to indicate a time zone at Universal Time. Though "-0000" also indicates Universal Time, it is used to indicate that the time was generated on a system that may be in a local time zone other than Universal Time and that the date-time contains no information about the local time zone.

ゾーンは、日付と時刻が表す協定世界時(UTC、以前は「グリニッジ標準時」と呼ばれていました)からのオフセットを指定します。 「+」または「-」は、時刻が世界時より進んでいる(つまり、東)か遅れている(つまり、西にある)かを示します。最初の2桁は世界時との時差の数を示し、最後の2桁は世界時との差の追加分数を示します。 (したがって、+ hhmmは+(hh * 60 + mm)分を意味し、-hhmmは-(hh * 60 + mm)分を意味します)。 「+0000」の形式を使用して、世界時のタイムゾーンを示す必要があります。 「-0000」は世界時も示しますが、世界時以外のローカルタイムゾーンにある可能性のあるシステムで時刻が生成されたこと、および日時にローカルタイムゾーンに関する情報が含まれていないことを示すために使用されます。

A date-time specification MUST be semantically valid. That is, the day-of-week (if included) MUST be the day implied by the date, the numeric day-of-month MUST be between 1 and the number of days allowed for the specified month (in the specified year), the time-of-day MUST be in the range 00:00:00 through 23:59:60 (the number of seconds allowing for a leap second; see [RFC1305]), and the last two digits of the zone MUST be within the range 00 through 59.


3.4. Address Specification
3.4. アドレス指定

Addresses occur in several message header fields to indicate senders and recipients of messages. An address may either be an individual mailbox, or a group of mailboxes.


address = mailbox / group


mailbox = name-addr / addr-spec

メールボックス= name-addr / addr-spec

name-addr = [display-name] angle-addr

name-addr = [display-name] angle-addr

   angle-addr      =   [CFWS] "<" addr-spec ">" [CFWS] /
   group           =   display-name ":" [group-list] ";" [CFWS]

display-name = phrase


   mailbox-list    =   (mailbox *("," mailbox)) / obs-mbox-list
   address-list    =   (address *("," address)) / obs-addr-list
   group-list      =   mailbox-list / CFWS / obs-group-list

A mailbox receives mail. It is a conceptual entity that does not necessarily pertain to file storage. For example, some sites may choose to print mail on a printer and deliver the output to the addressee's desk.


Normally, a mailbox is composed of two parts: (1) an optional display name that indicates the name of the recipient (which can be a person or a system) that could be displayed to the user of a mail application, and (2) an addr-spec address enclosed in angle brackets ("<" and ">"). There is an alternate simple form of a mailbox where the addr-spec address appears alone, without the recipient's name or the angle brackets. The Internet addr-spec address is described in section 3.4.1.

通常、メールボックスは次の2つの部分で構成されています。(1)メールアプリケーションのユーザーに表示できる受信者の名前を示すオプションの表示名(人またはシステム)。(2)山かっこ( "<"および ">")で囲まれたアドレス指定アドレス。受信者の名前や山かっこなしでaddr-specアドレスが単独で表示される、メールボックスの代替の単純な形式があります。インターネットaddr-specアドレスについては、セクション3.4.1で説明しています。

Note: Some legacy implementations used the simple form where the addr-spec appears without the angle brackets, but included the name of the recipient in parentheses as a comment following the addr-spec. Since the meaning of the information in a comment is unspecified, implementations SHOULD use the full name-addr form of the mailbox, instead of the legacy form, to specify the display name associated with a mailbox. Also, because some legacy implementations interpret the comment, comments generally SHOULD NOT be used in address fields to avoid confusing such implementations.


When it is desirable to treat several mailboxes as a single unit (i.e., in a distribution list), the group construct can be used. The group construct allows the sender to indicate a named group of recipients. This is done by giving a display name for the group, followed by a colon, followed by a comma-separated list of any number of mailboxes (including zero and one), and ending with a semicolon. Because the list of mailboxes can be empty, using the group construct is also a simple way to communicate to recipients that the message was sent to one or more named sets of recipients, without actually providing the individual mailbox address for any of those recipients.

複数のメールボックスを1つの単位として(つまり、配布リスト内で)扱うことが望ましい場合は、グループ構成を使用できます。 group構成では、送信者が名前付きの受信者グループを示すことができます。これは、グループの表示名、コロン、コンマで区切られた任意の数のメールボックス(0と1を含む)のリスト、セミコロンで終了することによって行われます。メールボックスのリストは空になる可能性があるため、グループ構成を使用すると、メッセージが1つ以上の名前付き受信者セットに送信されたことを受信者に伝える簡単な方法でもあります。

3.4.1. Addr-Spec Specification
3.4.1. Addr-Spec仕様

An addr-spec is a specific Internet identifier that contains a locally interpreted string followed by the at-sign character ("@", ASCII value 64) followed by an Internet domain. The locally interpreted string is either a quoted-string or a dot-atom. If the string can be represented as a dot-atom (that is, it contains no characters other than atext characters or "." surrounded by atext characters), then the dot-atom form SHOULD be used and the quoted-string form SHOULD NOT be used. Comments and folding white space SHOULD NOT be used around the "@" in the addr-spec.

addr-specは、ローカルで解釈される文字列の後にアットマーク文字( "@"、ASCII値64)が続き、その後にインターネットドメインが続く特定のインターネット識別子です。ローカルに解釈される文字列は、引用符付き文字列またはドット原子です。文字列をドットアトムとして表現できる場合(つまり、テキスト文字またはテキスト文字で囲まれた「。」以外の文字を含まない場合)、ドットアトム形式を使用する必要があり(SHOULD NOT)、引用文字列形式は使用しないでください(SHOULD NOT)利用される。コメントと折りたたみ空白は、addr-specの "@"の前後で使用しないでください。

Note: A liberal syntax for the domain portion of addr-spec is given here. However, the domain portion contains addressing information specified by and used in other protocols (e.g., [RFC1034], [RFC1035], [RFC1123], [RFC5321]). It is therefore incumbent upon implementations to conform to the syntax of addresses for the context in which they are used.


addr-spec = local-part "@" domain

addr-spec = local-part "@" domain

   local-part      =   dot-atom / quoted-string / obs-local-part
   domain          =   dot-atom / domain-literal / obs-domain

domain-literal = [CFWS] "[" *([FWS] dtext) [FWS] "]" [CFWS]

δομαίν-λίτεραλ= [ΣΦΩΣ] "[" *([ΦΩΣ]δτεξτ)[ΦΩΣ] "]" [ΣΦΩΣ]

   dtext           =   %d33-90 /          ; Printable US-ASCII
                       %d94-126 /         ;  characters not including
                       obs-dtext          ;  "[", "]", or "\"

The domain portion identifies the point to which the mail is delivered. In the dot-atom form, this is interpreted as an Internet domain name (either a host name or a mail exchanger name) as described in [RFC1034], [RFC1035], and [RFC1123]. In the domain-literal form, the domain is interpreted as the literal Internet address of the particular host. In both cases, how addressing is used and how messages are transported to a particular host is covered in separate documents, such as [RFC5321]. These mechanisms are outside of the scope of this document.


The local-part portion is a domain-dependent string. In addresses, it is simply interpreted on the particular host as a name of a particular mailbox.


3.5. Overall Message Syntax
3.5. 全体的なメッセージ構文

A message consists of header fields, optionally followed by a message body. Lines in a message MUST be a maximum of 998 characters excluding the CRLF, but it is RECOMMENDED that lines be limited to 78 characters excluding the CRLF. (See section 2.1.1 for explanation.) In a message body, though all of the characters listed in the text rule MAY be used, the use of US-ASCII control characters (values 1 through 8, 11, 12, and 14 through 31) is discouraged since their interpretation by receivers for display is not guaranteed.

メッセージはヘッダーフィールドで構成され、オプションでメッセージ本文が後に続きます。メッセージの行は、CRLFを除いて最大998文字にする必要がありますが、CRLFを除いて行を78文字に制限することをお勧めします。 (説明については、セクション2.1.1を参照してください。)メッセージ本文では、テキストルールにリストされているすべての文字を使用できますが、US-ASCII制御文字(値1〜8、11、12、および14〜 31)レシーバーによる表示の解釈が保証されていないため、推奨されません。

message = (fields / obs-fields) [CRLF body]

メッセージ=(フィールド/ obs-フィールド)[CRLF本文]

   body            =   (*(*998text CRLF) *998text) / obs-body
   text            =   %d1-9 /            ; Characters excluding CR
                       %d11 /             ;  and LF
                       %d12 /

The header fields carry most of the semantic information and are defined in section 3.6. The body is simply a series of lines of text that are uninterpreted for the purposes of this specification.


3.6. Field Definitions
3.6. フィールド定義

The header fields of a message are defined here. All header fields have the same general syntactic structure: a field name, followed by a colon, followed by the field body. The specific syntax for each header field is defined in the subsequent sections.


Note: In the ABNF syntax for each field in subsequent sections, each field name is followed by the required colon. However, for brevity, sometimes the colon is not referred to in the textual description of the syntax. It is, nonetheless, required.


It is important to note that the header fields are not guaranteed to be in a particular order. They may appear in any order, and they have been known to be reordered occasionally when transported over the Internet. However, for the purposes of this specification, header fields SHOULD NOT be reordered when a message is transported or transformed. More importantly, the trace header fields and resent header fields MUST NOT be reordered, and SHOULD be kept in blocks prepended to the message. See sections 3.6.6 and 3.6.7 for more information.

ヘッダーフィールドが特定の順序であるとは限らないことに注意してください。それらは任意の順序で表示される可能性があり、インターネット経由で転送されるときに時々再注文されることが知られています。ただし、この仕様では、メッセージが転送または変換されるときにヘッダーフィールドの順序を変更しないでください。さらに重要なのは、トレースヘッダーフィールドと再送信されたヘッダーフィールドを並べ替えてはならず(MUST NOT)、メッセージの前に付加されたブロックに保持する必要があります(SHOULD)。詳細については、セクション3.6.6および3.6.7を参照してください。

The only required header fields are the origination date field and the originator address field(s). All other header fields are syntactically optional. More information is contained in the table following this definition.


   fields          =   *(trace
                         *optional-field /
                         *(resent-date /
                          resent-from /
                          resent-sender /
                          resent-to /
                          resent-cc /
                          resent-bcc /
                       *(orig-date /
                       from /
                       sender /
                       reply-to /
                       to /
                       cc /
                       bcc /
                       message-id /
                       in-reply-to /
                       references /
                       subject /
                       comments /
                       keywords /

The following table indicates limits on the number of times each field may occur in the header section of a message as well as any special limitations on the use of those fields. An asterisk ("*") next to a value in the minimum or maximum column indicates that a special restriction appears in the Notes column.

次の表は、メッセージのヘッダーセクションで各フィールドが発生する回数の制限と、それらのフィールドの使用に関する特別な制限を示しています。最小または最大列の値の横にあるアスタリスク( "*")は、特記事項が[注記]列に表示されていることを示します。

   | Field          | Min    | Max number | Notes                      |
   |                | number |            |                            |
   | trace          | 0      | unlimited  | Block prepended - see      |
   |                |        |            | 3.6.7                      |
   | resent-date    | 0*     | unlimited* | One per block, required if |
   |                |        |            | other resent fields are    |
   |                |        |            | present - see 3.6.6        |
   | resent-from    | 0      | unlimited* | One per block - see 3.6.6  |
   | resent-sender  | 0*     | unlimited* | One per block, MUST occur  |
   |                |        |            | with multi-address         |
   |                |        |            | resent-from - see 3.6.6    |
   | resent-to      | 0      | unlimited* | One per block - see 3.6.6  |
   | resent-cc      | 0      | unlimited* | One per block - see 3.6.6  |
   | resent-bcc     | 0      | unlimited* | One per block - see 3.6.6  |
   | resent-msg-id  | 0      | unlimited* | One per block - see 3.6.6  |
   | orig-date      | 1      | 1          |                            |
   | from           | 1      | 1          | See sender and 3.6.2       |
   | sender         | 0*     | 1          | MUST occur with            |
   |                |        |            | multi-address from - see   |
   |                |        |            | 3.6.2                      |
   | reply-to       | 0      | 1          |                            |
   | to             | 0      | 1          |                            |
   | cc             | 0      | 1          |                            |
   | bcc            | 0      | 1          |                            |
   | message-id     | 0*     | 1          | SHOULD be present - see    |
   |                |        |            | 3.6.4                      |
   | in-reply-to    | 0*     | 1          | SHOULD occur in some       |
   |                |        |            | replies - see 3.6.4        |
   | references     | 0*     | 1          | SHOULD occur in some       |
   |                |        |            | replies - see 3.6.4        |
   | subject        | 0      | 1          |                            |
   | comments       | 0      | unlimited  |                            |
   | keywords       | 0      | unlimited  |                            |
   | optional-field | 0      | unlimited  |                            |

The exact interpretation of each field is described in subsequent sections.


3.6.1. The Origination Date Field
3.6.1. 開始日フィールド

The origination date field consists of the field name "Date" followed by a date-time specification.


orig-date = "Date:" date-time CRLF

orig-date = "Date:"日時CRLF

The origination date specifies the date and time at which the creator of the message indicated that the message was complete and ready to enter the mail delivery system. For instance, this might be the time that a user pushes the "send" or "submit" button in an application program. In any case, it is specifically not intended to convey the time that the message is actually transported, but rather the time at which the human or other creator of the message has put the message into its final form, ready for transport. (For example, a portable computer user who is not connected to a network might queue a message for delivery. The origination date is intended to contain the date and time that the user queued the message, not the time when the user connected to the network to send the message.)

発信日は、メッセージの作成者がメッセージが完了し、メール配信システムに入る準備ができたことを示した日時を示します。たとえば、ユーザーがアプリケーションプログラムの[送信]または[送信]ボタンを押すときなどです。いずれにせよ、メッセージが実際に転送される時間を伝えることは特に意図されておらず、メッセージの人間または他の作成者がメッセージを最終的な形式にして転送の準備ができた時間を伝えます。 (たとえば、ネットワークに接続していないポータブルコンピューターユーザーは、配信のためにメッセージをキューに入れることがあります。開始日には、ユーザーがネットワークに接続した時刻ではなく、ユーザーがメッセージをキューに入れた日付と時刻が含まれます。メッセージを送信します。)

3.6.2. Originator Fields
3.6.2. 発信者フィールド

The originator fields of a message consist of the from field, the sender field (when applicable), and optionally the reply-to field. The from field consists of the field name "From" and a comma-separated list of one or more mailbox specifications. If the from field contains more than one mailbox specification in the mailbox-list, then the sender field, containing the field name "Sender" and a single mailbox specification, MUST appear in the message. In either case, an optional reply-to field MAY also be included, which contains the field name "Reply-To" and a comma-separated list of one or more addresses.

メッセージの発信者フィールドは、送信者フィールド、送信者フィールド(該当する場合)、およびオプションで返信先フィールドで構成されます。差出人フィールドは、フィールド名「差出人」と、1つ以上のメールボックス指定のコンマ区切りリストで構成されます。 fromフィールドがメールボックスリストに複数のメールボックス指定を含む場合、フィールド名「Sender」と単一のメールボックス指定を含む送信者フィールドがメッセージに表示される必要があります。どちらの場合も、オプションの返信先フィールドを含めることができます。これには、フィールド名「Reply-To」と、1つ以上のアドレスのコンマ区切りリストが含まれます。

from = "From:" mailbox-list CRLF

from = "From:"メールボックスリストCRLF

sender = "Sender:" mailbox CRLF

sender = "Sender:"メールボックスCRLF

reply-to = "Reply-To:" address-list CRLF

reply-to = "Reply-To:"アドレスリストCRLF

The originator fields indicate the mailbox(es) of the source of the message. The "From:" field specifies the author(s) of the message, that is, the mailbox(es) of the person(s) or system(s) responsible for the writing of the message. The "Sender:" field specifies the mailbox of the agent responsible for the actual transmission of the message. For example, if a secretary were to send a message for another person, the mailbox of the secretary would appear in the "Sender:" field and the mailbox of the actual author would appear in the "From:" field. If the originator of the message can be indicated by a single mailbox and the author and transmitter are identical, the "Sender:" field SHOULD NOT be used. Otherwise, both fields SHOULD appear.

発信者フィールドは、メッセージの送信元のメールボックスを示します。 「From:」フィールドは、メッセージの作成者、つまりメッセージの書き込みを担当する人またはシステムのメールボックスを指定します。 「Sender:」フィールドは、メッセージの実際の送信を担当するエージェントのメールボックスを指定します。たとえば、秘書が別の人にメッセージを送信する場合、秘書のメールボックスは[送信者]フィールドに表示され、実際の作成者のメールボックスは[差出人]フィールドに表示されます。メッセージの発信者を単一のメールボックスで示すことができ、作成者と送信者が同一である場合、「送信者:」フィールドは使用してはなりません(SHOULD NOT)。それ以外の場合は、両方のフィールドが表示されるべきです(SHOULD)。

Note: The transmitter information is always present. The absence of the "Sender:" field is sometimes mistakenly taken to mean that the agent responsible for transmission of the message has not been specified. This absence merely means that the transmitter is identical to the author and is therefore not redundantly placed into the "Sender:" field.

注:トランスミッター情報は常に表示されます。 「Sender:」フィールドがないことは、メッセージの送信を担当するエージェントが指定されていないことを誤って解釈していることがあります。この不在は、送信者が作成者と同一であることを意味するだけであり、したがって "Sender:"フィールドに重複して配置されることはありません。

The originator fields also provide the information required when replying to a message. When the "Reply-To:" field is present, it indicates the address(es) to which the author of the message suggests that replies be sent. In the absence of the "Reply-To:" field, replies SHOULD by default be sent to the mailbox(es) specified in the "From:" field unless otherwise specified by the person composing the reply.

発信者フィールドは、メッセージに返信するときに必要な情報も提供します。 「Reply-To:」フィールドが存在する場合、メッセージの作成者が返信の送信を提案するアドレスを示します。 「Reply-To:」フィールドがない場合、返信は、返信の作成者が特に指定しない限り、「From:」フィールドで指定されたメールボックスにデフォルトで送信される必要があります(SHOULD)。

In all cases, the "From:" field SHOULD NOT contain any mailbox that does not belong to the author(s) of the message. See also section 3.6.3 for more information on forming the destination addresses for a reply.


3.6.3. Destination Address Fields
3.6.3. 宛先アドレスフィールド

The destination fields of a message consist of three possible fields, each of the same form: the field name, which is either "To", "Cc", or "Bcc", followed by a comma-separated list of one or more addresses (either mailbox or group syntax).

メッセージの宛先フィールドは、同じ形式の3つの可能なフィールドで構成されます。「To」、「Cc」、または「Bcc」のいずれかであるフィールド名の後に、1つ以上のアドレスのコンマ区切りリストが続きます。 (メールボックスまたはグループ構文)。

to = "To:" address-list CRLF

to = "To:"アドレスリストCRLF

cc = "Cc:" address-list CRLF

cc = "Cc:"アドレスリストCRLF

   bcc             =   "Bcc:" [address-list / CFWS] CRLF

The destination fields specify the recipients of the message. Each destination field may have one or more addresses, and the addresses indicate the intended recipients of the message. The only difference between the three fields is how each is used.

宛先フィールドは、メッセージの受信者を指定します。各宛先フィールドは1つ以上のアドレスを持つことができ、アドレスはメッセージの意図された受信者を示します。 3つのフィールドの唯一の違いは、それぞれの使用方法です。

The "To:" field contains the address(es) of the primary recipient(s) of the message.


The "Cc:" field (where the "Cc" means "Carbon Copy" in the sense of making a copy on a typewriter using carbon paper) contains the addresses of others who are to receive the message, though the content of the message may not be directed at them.


The "Bcc:" field (where the "Bcc" means "Blind Carbon Copy") contains addresses of recipients of the message whose addresses are not to be revealed to other recipients of the message. There are three ways in which the "Bcc:" field is used. In the first case, when a message containing a "Bcc:" field is prepared to be sent, the "Bcc:" line is removed even though all of the recipients (including those specified in the "Bcc:" field) are sent a copy of the message. In the second case, recipients specified in the "To:" and "Cc:" lines each are sent a copy of the message with the "Bcc:" line removed as above, but the recipients on the "Bcc:" line get a separate copy of the message containing a "Bcc:" line. (When there are multiple recipient addresses in the "Bcc:" field, some implementations actually send a separate copy of the message to each recipient with a "Bcc:" containing only the address of that particular recipient.) Finally, since a "Bcc:" field may contain no addresses, a "Bcc:" field can be sent without any addresses indicating to the recipients that blind copies were sent to someone. Which method to use with "Bcc:" fields is implementation dependent, but refer to the "Security Considerations" section of this document for a discussion of each.

「Bcc:」フィールド(「Bcc」は「ブラインドカーボンコピー」を意味します)には、メッセージの受信者のアドレスが含まれ、そのアドレスはメッセージの他の受信者には公開されません。 「Bcc:」フィールドを使用する方法は3つあります。最初のケースでは、「Bcc:」フィールドを含むメッセージを送信する準備ができると、すべての受信者(「Bcc:」フィールドで指定されたものを含む)が送信されても​​、「Bcc:」行が削除されます。メッセージのコピー。 2番目のケースでは、「To:」行と「Cc:」行で指定された受信者にはそれぞれ、上記のように「Bcc:」行が削除されたメッセージのコピーが送信されますが、「Bcc:」行の受信者は「Bcc:」行を含むメッセージの個別のコピー。 (「Bcc:」フィールドに複数の受信者アドレスがある場合、一部の実装では、特定の受信者のアドレスのみを含む「Bcc:」を使用して、メッセージの個別のコピーを実際に各受信者に送信します。)最後に、「Bcc: : "フィールドにはアドレスが含まれていない場合があります。" Bcc: "フィールドは、ブラインドコピーが誰かに送信されたことを受信者に示すアドレスなしで送信できます。 「Bcc:」フィールドで使用する方法は実装によって異なりますが、それぞれの説明については、このドキュメントの「セキュリティに関する考慮事項」セクションを参照してください。

When a message is a reply to another message, the mailboxes of the authors of the original message (the mailboxes in the "From:" field) or mailboxes specified in the "Reply-To:" field (if it exists) MAY appear in the "To:" field of the reply since these would normally be the primary recipients of the reply. If a reply is sent to a message that has destination fields, it is often desirable to send a copy of the reply to all of the recipients of the message, in addition to the author. When such a reply is formed, addresses in the "To:" and "Cc:" fields of the original message MAY appear in the "Cc:" field of the reply, since these are normally secondary recipients of the reply. If a "Bcc:" field is present in the original message, addresses in that field MAY appear in the "Bcc:" field of the reply, but they SHOULD NOT appear in the "To:" or "Cc:" fields.

メッセージが別のメッセージへの返信である場合、元のメッセージの作成者のメールボックス(「From:」フィールドのメールボックス)または「Reply-To:」フィールドで指定されたメールボックス(存在する場合)は、これらは通常、返信の主要な受信者であるため、返信の「宛先」フィールド。宛先フィールドを持つメッセージに返信が送信される場合、作成者に加えて、メッセージのすべての受信者に返信のコピーを送信することが望ましい場合があります。このような返信が形成されると、元のメッセージの "To:"および "Cc:"フィールドのアドレスは、通常は返信の2次受信者であるため、返信の "Cc:"フィールドに表示される場合があります。元のメッセージに「Bcc:」フィールドが存在する場合、そのフィールドのアドレスは返信の「Bcc:」フィールドに表示される場合がありますが、「To:」または「Cc:」フィールドには表示されません(SHOULD NOT)。

Note: Some mail applications have automatic reply commands that include the destination addresses of the original message in the destination addresses of the reply. How those reply commands behave is implementation dependent and is beyond the scope of this document. In particular, whether or not to include the original destination addresses when the original message had a "Reply-To:" field is not addressed here.


3.6.4. Identification Fields
3.6.4. 識別フィールド

Though listed as optional in the table in section 3.6, every message SHOULD have a "Message-ID:" field. Furthermore, reply messages SHOULD have "In-Reply-To:" and "References:" fields as appropriate and as described below.


The "Message-ID:" field contains a single unique message identifier. The "References:" and "In-Reply-To:" fields each contain one or more unique message identifiers, optionally separated by CFWS.

「Message-ID:」フィールドには、単一の一意のメッセージ識別子が含まれます。 「References:」および「In-Reply-To:」フィールドにはそれぞれ、1つ以上の一意のメッセージ識別子が含まれ、オプションでCFWSで区切られます。

The message identifier (msg-id) syntax is a limited version of the addr-spec construct enclosed in the angle bracket characters, "<" and ">". Unlike addr-spec, this syntax only permits the dot-atom-text form on the left-hand side of the "@" and does not have internal CFWS anywhere in the message identifier.

メッセージ識別子(msg-id)構文は、山かっこ文字「<」および「>」で囲まれたaddr-spec構成の限定バージョンです。 addr-specとは異なり、この構文では「@」の左側にあるドットアトムテキスト形式のみが許可され、メッセージ識別子のどこにも内部CFWSがありません。

Note: As with addr-spec, a liberal syntax is given for the right-hand side of the "@" in a msg-id. However, later in this section, the use of a domain for the right-hand side of the "@" is RECOMMENDED. Again, the syntax of domain constructs is specified by and used in other protocols (e.g., [RFC1034], [RFC1035], [RFC1123], [RFC5321]). It is therefore incumbent upon implementations to conform to the syntax of addresses for the context in which they are used.


message-id = "Message-ID:" msg-id CRLF

message-id = "Message-ID:" msg-id CRLF

   in-reply-to     =   "In-Reply-To:" 1*msg-id CRLF
   references      =   "References:" 1*msg-id CRLF
   msg-id          =   [CFWS] "<" id-left "@" id-right ">" [CFWS]

id-left = dot-atom-text / obs-id-left

id-left = dot-atom-text / obs-id-left

   id-right        =   dot-atom-text / no-fold-literal / obs-id-right

no-fold-literal = "[" *dtext "]"

no-fold-literal = "[" * text "]

The "Message-ID:" field provides a unique message identifier that refers to a particular version of a particular message. The uniqueness of the message identifier is guaranteed by the host that generates it (see below). This message identifier is intended to be machine readable and not necessarily meaningful to humans. A message identifier pertains to exactly one version of a particular message; subsequent revisions to the message each receive new message identifiers.


Note: There are many instances when messages are "changed", but those changes do not constitute a new instantiation of that message, and therefore the message would not get a new message identifier. For example, when messages are introduced into the transport system, they are often prepended with additional header fields such as trace fields (described in section 3.6.7) and resent fields (described in section 3.6.6). The addition of such header fields does not change the identity of the message and therefore the original "Message-ID:" field is retained. In all cases, it is the meaning that the sender of the message wishes to convey (i.e., whether this is the same message or a different message) that determines whether or not the "Message-ID:" field changes, not any particular syntactic difference that appears (or does not appear) in the message.


The "In-Reply-To:" and "References:" fields are used when creating a reply to a message. They hold the message identifier of the original message and the message identifiers of other messages (for example, in the case of a reply to a message that was itself a reply). The "In-Reply-To:" field may be used to identify the message (or messages) to which the new message is a reply, while the "References:" field may be used to identify a "thread" of conversation.

「In-Reply-To:」および「References:」フィールドは、メッセージへの返信を作成するときに使用されます。元のメッセージのメッセージ識別子と他のメッセージのメッセージ識別子を保持します(たとえば、それ自体が返信であったメッセージへの返信の場合)。 「In-Reply-To:」フィールドは、新しいメッセージが返信される1つまたは複数のメッセージを識別するために使用でき、「References:」フィールドは、会話の「スレッド」を識別するために使用できます。

When creating a reply to a message, the "In-Reply-To:" and "References:" fields of the resultant message are constructed as follows:


The "In-Reply-To:" field will contain the contents of the "Message-ID:" field of the message to which this one is a reply (the "parent message"). If there is more than one parent message, then the "In-Reply-To:" field will contain the contents of all of the parents' "Message-ID:" fields. If there is no "Message-ID:" field in any of the parent messages, then the new message will have no "In-Reply-To:" field.


The "References:" field will contain the contents of the parent's "References:" field (if any) followed by the contents of the parent's "Message-ID:" field (if any). If the parent message does not contain a "References:" field but does have an "In-Reply-To:" field containing a single message identifier, then the "References:" field will contain the contents of the parent's "In-Reply-To:" field followed by the contents of the parent's "Message-ID:" field (if any). If the parent has none of the "References:", "In-Reply-To:", or "Message-ID:" fields, then the new message will have no "References:" field.

「参照:」フィールドには、親の「参照:」フィールド(存在する場合)の内容と、その後に親の「メッセージID:」フィールド(存在する場合)の内容が含まれます。親メッセージに「References:」フィールドが含まれていないが、単一のメッセージ識別子を含む「In-Reply-To:」フィールドがある場合、「References:」フィールドには親の「In-Reply」の内容が含まれます-To: "フィールドの後に、親の" Message-ID: "フィールド(存在する場合)の内容が続きます。親に「References:」、「In-Reply-To:」、または「Message-ID:」フィールドがない場合、新しいメッセージには「References:」フィールドがありません。

Note: Some implementations parse the "References:" field to display the "thread of the discussion". These implementations assume that each new message is a reply to a single parent and hence that they can walk backwards through the "References:" field to find the parent of each message listed there. Therefore, trying to form a "References:" field for a reply that has multiple parents is discouraged; how to do so is not defined in this document.


The message identifier (msg-id) itself MUST be a globally unique identifier for a message. The generator of the message identifier MUST guarantee that the msg-id is unique. There are several algorithms that can be used to accomplish this. Since the msg-id has a similar syntax to addr-spec (identical except that quoted strings, comments, and folding white space are not allowed), a good method is to put the domain name (or a domain literal IP address) of the host on which the message identifier was created on the right-hand side of the "@" (since domain names and IP addresses are normally unique), and put a combination of the current absolute date and time along with some other currently unique (perhaps sequential) identifier available on the system (for example, a process id number) on the left-hand side. Though other algorithms will work, it is RECOMMENDED that the right-hand side contain some domain identifier (either of the host itself or otherwise) such that the generator of the message identifier can guarantee the uniqueness of the left-hand side within the scope of that domain.

メッセージ識別子(msg-id)自体は、メッセージのグローバルに一意の識別子である必要があります。メッセージ識別子のジェネレータは、msg-idが一意であることを保証する必要があります。これを達成するために使用できるいくつかのアルゴリズムがあります。 msg-idの構文はaddr-specと似ているため(引用符付きの文字列、コメント、折りたたみ空白は許可されないことを除いて同じ)、適切な方法は、ドメイン名(またはドメインリテラルIPアドレス)を置くことです。 「@」の右側にメッセージIDが作成されたホスト(ドメイン名とIPアドレスは通常は一意であるため)、現在の絶対日時と他の現在一意の(おそらくは左側のシステムで使用可能なID(たとえば、プロセスID番号)。他のアルゴリズムでも機能しますが、メッセージ識別子のジェネレーターがスコープの範囲内で左側の一意性を保証できるように、右側にドメイン識別子(ホスト自体またはその他)が含まれていることが推奨されますそのドメイン。

Semantically, the angle bracket characters are not part of the msg-id; the msg-id is what is contained between the two angle bracket characters.

意味的に、山かっこ文字はmsg-idの一部ではありません。 msg-idは、2つの山括弧文字の間に含まれるものです。

3.6.5. Informational Fields
3.6.5. 情報フィールド

The informational fields are all optional. The "Subject:" and "Comments:" fields are unstructured fields as defined in section 2.2.1, and therefore may contain text or folding white space. The "Keywords:" field contains a comma-separated list of one or more words or quoted-strings.

情報フィールドはすべてオプションです。 「Subject:」および「Comments:」フィールドは、セクション2.2.1で定義されている非構造化フィールドであるため、テキストまたは折りたたみ空白を含めることができます。 「Keywords:」フィールドには、1つ以上の単語または引用文字列のコンマ区切りリストが含まれています。

subject = "Subject:" unstructured CRLF

件名= "件名:"非構造化CRLF

comments = "Comments:" unstructured CRLF

コメント= "コメント:"非構造化CRLF

   keywords        =   "Keywords:" phrase *("," phrase) CRLF

These three fields are intended to have only human-readable content with information about the message. The "Subject:" field is the most common and contains a short string identifying the topic of the message. When used in a reply, the field body MAY start with the string "Re: " (an abbreviation of the Latin "in re", meaning "in the matter of") followed by the contents of the "Subject:" field body of the original message. If this is done, only one instance of the literal string "Re: " ought to be used since use of other strings or more than one instance can lead to undesirable consequences. The "Comments:" field contains any additional comments on the text of the body of the message. The "Keywords:" field contains a comma-separated list of important words and phrases that might be useful for the recipient.

これらの3つのフィールドは、メッセージに関する情報を含む、人間が読めるコンテンツのみを持つことを目的としています。 「件名:」フィールドは最も一般的で、メッセージのトピックを識別する短い文字列が含まれています。返信で使用する場合、フィールド本文は文字列 "Re:"(ラテン語での "in re"の略語。 "in the subject of"を意味する)で始まり、その後に "Subject:"フィールド本文の内容が続きます。元のメッセージ。これが行われる場合、他の文字列または複数のインスタンスを使用すると望ましくない結果が生じる可能性があるため、リテラル文字列「Re:」のインスタンスを1つだけ使用する必要があります。 「コメント:」フィールドには、メッセージ本文のテキストに関する追加のコメントが含まれます。 「Keywords:」フィールドには、受信者に役立つ可能性のある重要な単語とフレーズのコンマ区切りのリストが含まれています。

3.6.6. Resent Fields
3.6.6. 再送フィールド

Resent fields SHOULD be added to any message that is reintroduced by a user into the transport system. A separate set of resent fields SHOULD be added each time this is done. All of the resent fields corresponding to a particular resending of the message SHOULD be grouped together. Each new set of resent fields is prepended to the message; that is, the most recent set of resent fields appears earlier in the message. No other fields in the message are changed when resent fields are added.


Each of the resent fields corresponds to a particular field elsewhere in the syntax. For instance, the "Resent-Date:" field corresponds to the "Date:" field and the "Resent-To:" field corresponds to the "To:" field. In each case, the syntax for the field body is identical to the syntax given previously for the corresponding field.


When resent fields are used, the "Resent-From:" and "Resent-Date:" fields MUST be sent. The "Resent-Message-ID:" field SHOULD be sent. "Resent-Sender:" SHOULD NOT be used if "Resent-Sender:" would be identical to "Resent-From:".

再送フィールドを使用する場合は、「Resent-From:」および「Resent-Date:」フィールドを送信する必要があります。 「Resent-Message-ID:」フィールドを送信する必要があります。 「Resent-Sender:」は、「Resent-Sender:」が「Resent-From:」と同じになる場合は使用しないでください。

resent-date = "Resent-Date:" date-time CRLF

resent-date = "Resent-Date:"日時CRLF

resent-from = "Resent-From:" mailbox-list CRLF

resent-from = "Resent-From:"メールボックスリストCRLF

resent-sender = "Resent-Sender:" mailbox CRLF

resent-sender = "Resent-Sender:"メールボックスCRLF

resent-to = "Resent-To:" address-list CRLF

resent-to = "Resent-To:"アドレスリストCRLF

resent-cc = "Resent-Cc:" address-list CRLF

resent-cc = "Resent-Cc:"アドレスリストCRLF

   resent-bcc      =   "Resent-Bcc:" [address-list / CFWS] CRLF

resent-msg-id = "Resent-Message-ID:" msg-id CRLF Resent fields are used to identify a message as having been reintroduced into the transport system by a user. The purpose of using resent fields is to have the message appear to the final recipient as if it were sent directly by the original sender, with all of the original fields remaining the same. Each set of resent fields correspond to a particular resending event. That is, if a message is resent multiple times, each set of resent fields gives identifying information for each individual time. Resent fields are strictly informational. They MUST NOT be used in the normal processing of replies or other such automatic actions on messages.

resent-msg-id = "Resent-Message-ID:" msg-id CRLF再送フィールドは、メッセージがユーザーによってトランスポートシステムに再導入されたことを識別するために使用されます。再送信されたフィールドを使用する目的は、元の送信者から直接送信されたかのようにメッセージを最終的な受信者に表示し、元のフィールドはすべて同じままにすることです。再送信フィールドの各セットは、特定の再送信イベントに対応しています。つまり、メッセージが複数回再送信される場合、再送信フィールドの各セットは、個々の時間ごとに識別情報を提供します。再送フィールドは、情報提供のみを目的としています。これらは、メッセージの通常の返信処理または他のそのような自動アクションで使用してはなりません(MUST NOT)。

Note: Reintroducing a message into the transport system and using resent fields is a different operation from "forwarding". "Forwarding" has two meanings: One sense of forwarding is that a mail reading program can be told by a user to forward a copy of a message to another person, making the forwarded message the body of the new message. A forwarded message in this sense does not appear to have come from the original sender, but is an entirely new message from the forwarder of the message. Forwarding may also mean that a mail transport program gets a message and forwards it on to a different destination for final delivery. Resent header fields are not intended for use with either type of forwarding.

注:メッセージをトランスポートシステムに再導入し、再送信フィールドを使用することは、「転送」とは異なる操作です。 「転送」には2つの意味があります。転送の1つの意味は、ユーザーがメールの読み取りプログラムにメッセージのコピーを別の人に転送し、転送されたメッセージを新しいメッセージの本文にすることです。この意味で転送されたメッセージは、元の送信者から送信されたようには見えませんが、メッセージの転送者からのまったく新しいメッセージです。転送は、メールトランスポートプログラムがメッセージを取得し、最終的な配信のために別の宛先に転送することも意味します。再送信されたヘッダーフィールドは、どちらのタイプの転送でも使用するためのものではありません。

The resent originator fields indicate the mailbox of the person(s) or system(s) that resent the message. As with the regular originator fields, there are two forms: a simple "Resent-From:" form, which contains the mailbox of the individual doing the resending, and the more complex form, when one individual (identified in the "Resent-Sender:" field) resends a message on behalf of one or more others (identified in the "Resent-From:" field).

再送信元のフィールドは、メッセージを再送信した人またはシステムのメールボックスを示します。通常の発信者フィールドと同様に、2つの形式があります。再送信を行う個人のメールボックスを含む単純な "Resent-From:"フォームと、1人の個人( "Resent-Sender : "フィールド)は、1つ以上の他のユーザーに代わってメッセージを再送信します(" Resent-From: "フィールドで識別されます)。

Note: When replying to a resent message, replies behave just as they would with any other message, using the original "From:", "Reply-To:", "Message-ID:", and other fields. The resent fields are only informational and MUST NOT be used in the normal processing of replies.


The "Resent-Date:" indicates the date and time at which the resent message is dispatched by the resender of the message. Like the "Date:" field, it is not the date and time that the message was actually transported.

「Resent-Date:」は、メッセージの再送信者によって再送信されたメッセージがディスパッチされる日時を示します。 「Date:」フィールドと同様に、メッセージが実際に転送された日時ではありません。

The "Resent-To:", "Resent-Cc:", and "Resent-Bcc:" fields function identically to the "To:", "Cc:", and "Bcc:" fields, respectively, except that they indicate the recipients of the resent message, not the recipients of the original message.


The "Resent-Message-ID:" field provides a unique identifier for the resent message.


3.6.7. Trace Fields
3.6.7. トレースフィールド

The trace fields are a group of header fields consisting of an optional "Return-Path:" field, and one or more "Received:" fields. The "Return-Path:" header field contains a pair of angle brackets that enclose an optional addr-spec. The "Received:" field contains a (possibly empty) list of tokens followed by a semicolon and a date-time specification. Each token must be a word, angle-addr, addr-spec, or a domain. Further restrictions are applied to the syntax of the trace fields by specifications that provide for their use, such as [RFC5321].

トレースフィールドは、オプションの「Return-Path:」フィールドと1つ以上の「Received:」フィールドで構成されるヘッダーフィールドのグループです。 「Return-Path:」ヘッダーフィールドには、オプションのaddr-specを囲む一対の山括弧が含まれています。 「Received:」フィールドには、セミコロンと日時指定が後に続くトークンの(空の可能性がある)リストが含まれています。各トークンは、単語、angle-addr、addr-spec、またはドメインである必要があります。 [RFC5321]などの使用を提供する仕様によって、トレースフィールドの構文にさらに制限が適用されます。

trace = [return] 1*received

trace = [return] 1 * received

return = "Return-Path:" path CRLF

return = "Return-Path:"パスCRLF

   path            =   angle-addr / ([CFWS] "<" [CFWS] ">" [CFWS])
   received        =   "Received:" *received-token ";" date-time CRLF
   received-token  =   word / angle-addr / addr-spec / domain

A full discussion of the Internet mail use of trace fields is contained in [RFC5321]. For the purposes of this specification, the trace fields are strictly informational, and any formal interpretation of them is outside of the scope of this document.


3.6.8. Optional Fields
3.6.8. オプションのフィールド

Fields may appear in messages that are otherwise unspecified in this document. They MUST conform to the syntax of an optional-field. This is a field name, made up of the printable US-ASCII characters except SP and colon, followed by a colon, followed by any text that conforms to the unstructured syntax.


The field names of any optional field MUST NOT be identical to any field name specified elsewhere in this document.


optional-field = field-name ":" unstructured CRLF

optional-field = field-name ":"非構造化CRLF

field-name = 1*ftext

フィールド名= 1 * ftext

ftext = %d33-57 / ; Printable US-ASCII %d59-126 ; characters not including ; ":".

ftext =%d33-57 /;印刷可能なUS-ASCII%d59-126;含まない文字「:」。

For the purposes of this specification, any optional field is uninterpreted.


4. Obsolete Syntax
4. 廃止された構文

Earlier versions of this specification allowed for different (usually more liberal) syntax than is allowed in this version. Also, there have been syntactic elements used in messages on the Internet whose interpretations have never been documented. Though these syntactic forms MUST NOT be generated according to the grammar in section 3, they MUST be accepted and parsed by a conformant receiver. This section documents many of these syntactic elements. Taking the grammar in section 3 and adding the definitions presented in this section will result in the grammar to use for the interpretation of messages.

この仕様の以前のバージョンでは、このバージョンで許可されているものとは異なる(通常はより自由な)構文が許可されていました。また、インターネット上のメッセージで使用されている構文要素があり、その解釈は文書化されていません。これらの構文形式は、セクション3の文法に従って生成してはならない(MUST NOT)が、それらは適合レシーバーによって受け入れられ、解析されなければならない(MUST)。このセクションでは、これらの構文要素の多くについて説明します。セクション3の文法を採用し、このセクションで提示されている定義を追加すると、文法がメッセージの解釈に使用されます。

Note: This section identifies syntactic forms that any implementation MUST reasonably interpret. However, there are certainly Internet messages that do not conform to even the additional syntax given in this section. The fact that a particular form does not appear in any section of this document is not justification for computer programs to crash or for malformed data to be irretrievably lost by any implementation. It is up to the implementation to deal with messages robustly.


One important difference between the obsolete (interpreting) and the current (generating) syntax is that in structured header field bodies (i.e., between the colon and the CRLF of any structured header field), white space characters, including folding white space, and comments could be freely inserted between any syntactic tokens. This allowed many complex forms that have proven difficult for some implementations to parse.


Another key difference between the obsolete and the current syntax is that the rule in section 3.2.2 regarding lines composed entirely of white space in comments and folding white space does not apply. See the discussion of folding white space in section 4.2 below.


Finally, certain characters that were formerly allowed in messages appear in this section. The NUL character (ASCII value 0) was once allowed, but is no longer for compatibility reasons. Similarly, US-ASCII control characters other than CR, LF, SP, and HTAB (ASCII values 1 through 8, 11, 12, 14 through 31, and 127) were allowed to appear in header field bodies. CR and LF were allowed to appear in messages other than as CRLF; this use is also shown here.

最後に、以前メッセージで許可されていた特定の文字がこのセクションに表示されます。 NUL文字(ASCII値0)は、以前は許可されていましたが、互換性の理由で使用できなくなりました。同様に、CR、LF、SP、およびHTAB以外のUS-ASCII制御文字(ASCII値1〜8、11、12、14〜31、および127)は、ヘッダーフィールドの本文に表示できました。 CRおよびLFは、CRLF以外のメッセージに表示されることが許可されていました。この使用法もここに示されています。

Other differences in syntax and semantics are noted in the following sections.


4.1. Miscellaneous Obsolete Tokens
4.1. その他の廃止されたトークン

These syntactic elements are used elsewhere in the obsolete syntax or in the main syntax. Bare CR, bare LF, and NUL are added to obs-qp, obs-body, and obs-unstruct. US-ASCII control characters are added to obs-qp, obs-unstruct, obs-ctext, and obs-qtext. The period character is added to obs-phrase. The obs-phrase-list provides for a (potentially empty) comma-separated list of phrases that may include "null" elements. That is, there could be two or more commas in such a list with nothing in between them, or commas at the beginning or end of the list.

これらの構文要素は、廃止された構文またはメイン構文の別の場所で使用されています。ベアCR、ベアLF、NULがobs-qp、obs-body、およびobs-unstructに追加されました。 US-ASCII制御文字がobs-qp、obs-unstruct、obs-ctext、およびobs-qtextに追加されました。ピリオド文字がobs-phraseに追加されます。 obs-phrase-listは、「null」要素を含む可能性のある、コンマで区切られた(潜在的に空の)フレーズのリストを提供します。つまり、このようなリストには、間に何もないコンマが2つ以上あるか、リストの最初または最後にコンマが含まれている可能性があります。

Note: The "period" (or "full stop") character (".") in obs-phrase is not a form that was allowed in earlier versions of this or any other specification. Period (nor any other character from specials) was not allowed in phrase because it introduced a parsing difficulty distinguishing between phrases and portions of an addr-spec (see section 4.4). It appears here because the period character is currently used in many messages in the display-name portion of addresses, especially for initials in names, and therefore must be interpreted properly.


   obs-NO-WS-CTL   =   %d1-8 /            ; US-ASCII control
                       %d11 /             ;  characters that do not
                       %d12 /             ;  include the carriage
                       %d14-31 /          ;  return, line feed, and
                       %d127              ;  white space characters

obs-ctext = obs-NO-WS-CTL

obs-ctext = obs-NO-WS-CTL

obs-qtext = obs-NO-WS-CTL

obs-qtext = obs-NO-WS-CTL

   obs-utext       =   %d0 / obs-NO-WS-CTL / VCHAR
   obs-qp          =   "\" (%d0 / obs-NO-WS-CTL / LF / CR)
   obs-body        =   *((*LF *CR *((%d0 / text) *LF *CR)) / CRLF)
   obs-unstruct    =   *((*LF *CR *(obs-utext *LF *CR)) / FWS) obs-phrase      =   word *(word / "." / CFWS)
   obs-phrase-list =   [phrase / CFWS] *("," [phrase / CFWS])

Bare CR and bare LF appear in messages with two different meanings. In many cases, bare CR or bare LF are used improperly instead of CRLF to indicate line separators. In other cases, bare CR and bare LF are used simply as US-ASCII control characters with their traditional ASCII meanings.


4.2. Obsolete Folding White Space
4.2. 廃止された折りたたみ空白

In the obsolete syntax, any amount of folding white space MAY be inserted where the obs-FWS rule is allowed. This creates the possibility of having two consecutive "folds" in a line, and therefore the possibility that a line which makes up a folded header field could be composed entirely of white space.


   obs-FWS         =   1*WSP *(CRLF 1*WSP)
4.3. Obsolete Date and Time
4.3. 廃止された日付と時刻

The syntax for the obsolete date format allows a 2 digit year in the date field and allows for a list of alphabetic time zone specifiers that were used in earlier versions of this specification. It also permits comments and folding white space between many of the tokens.


obs-day-of-week = [CFWS] day-name [CFWS]

obs-day-of-week = [CFWS] day-name [CFWS]

obs-day = [CFWS] 1*2DIGIT [CFWS]

obs-day = [CFWS] 1 * 2DIGIT [CFWS]

obs-year = [CFWS] 2*DIGIT [CFWS]

obs-year = [CFWS] 2 * DIGIT [CFWS]

obs-hour = [CFWS] 2DIGIT [CFWS]

obs-hour = [CFWS] 2DIGIT [CFWS]

obs-minute = [CFWS] 2DIGIT [CFWS]

obs-minute = [CFWS] 2DIGIT [CFWS]

obs-second = [CFWS] 2DIGIT [CFWS]

obs-second = [CFWS] 2DIGIT [CFWS]

   obs-zone        =   "UT" / "GMT" /     ; Universal Time
                                          ; North American UT
                                          ; offsets
                       "EST" / "EDT" /    ; Eastern:  - 5/ - 4
                       "CST" / "CDT" /    ; Central:  - 6/ - 5
                       "MST" / "MDT" /    ; Mountain: - 7/ - 6
                       "PST" / "PDT" /    ; Pacific:  - 8/ - 7
                       %d65-73 /          ; Military zones - "A"
                       %d75-90 /          ; through "I" and "K"
                       %d97-105 /         ; through "Z", both
                       %d107-122          ; upper and lower case

Where a two or three digit year occurs in a date, the year is to be interpreted as follows: If a two digit year is encountered whose value is between 00 and 49, the year is interpreted by adding 2000, ending up with a value between 2000 and 2049. If a two digit year is encountered with a value between 50 and 99, or any three digit year is encountered, the year is interpreted by adding 1900.

日付に2桁または3桁の年が含まれる場合、年は次のように解釈されます。00から49までの値を持つ2桁の年に遭遇した場合、年は2000を追加して解釈され、 2000と2049。2桁の年が50〜99の値で検出された場合、または3桁の年が検出された場合、年は1900を追加して解釈されます。

In the obsolete time zone, "UT" and "GMT" are indications of "Universal Time" and "Greenwich Mean Time", respectively, and are both semantically identical to "+0000".


The remaining three character zones are the US time zones. The first letter, "E", "C", "M", or "P" stands for "Eastern", "Central", "Mountain", and "Pacific". The second letter is either "S" for "Standard" time, or "D" for "Daylight Savings" (or summer) time. Their interpretations are as follows:

残りの3つの文字ゾーンは、米国のタイムゾーンです。最初の文字「E」、「C」、「M」、または「P」は、「東部」、「中央部」、「山」、および「太平洋」を表します。 2番目の文字は、「標準」時間の「S」、または「夏時間」(または夏)時間の「D」のいずれかです。それらの解釈は次のとおりです。

EDT is semantically equivalent to -0400 EST is semantically equivalent to -0500 CDT is semantically equivalent to -0500 CST is semantically equivalent to -0600 MDT is semantically equivalent to -0600 MST is semantically equivalent to -0700 PDT is semantically equivalent to -0700 PST is semantically equivalent to -0800

EDTは意味的に-0400に等しいESTは意味的に-0500に等しいCDTは意味的に-0500に等しいCSTは意味的に-0600に等しいMDTは意味的に-0600に等しいMSTは意味的に-0700に等しいPDTは意味的に-0700 PSTに等しい意味的に-0800と同等

The 1 character military time zones were defined in a non-standard way in [RFC0822] and are therefore unpredictable in their meaning. The original definitions of the military zones "A" through "I" are equivalent to "+0100" through "+0900", respectively; "K", "L", and "M" are equivalent to "+1000", "+1100", and "+1200", respectively; "N" through "Y" are equivalent to "-0100" through "-1200". respectively; and "Z" is equivalent to "+0000". However, because of the error in [RFC0822], they SHOULD all be considered equivalent to "-0000" unless there is out-of-band information confirming their meaning.

1文字のミリタリータイムゾーンは[RFC0822]で非標準的な方法で定義されているため、その意味は予測できません。軍事ゾーン "A"から "I"の元の定義は、それぞれ "+0100"から "+0900"に相当します。 「K」、「L」、「M」は、それぞれ「+1000」、「+ 1100」、「+ 1200」と同等です。 「N」から「Y」は「-0100」から「-1200」と同等です。それぞれ; 「Z」は「+0000」と同等です。ただし、[RFC0822]のエラーのため、それらの意味を確認する帯域外情報がない限り、それらはすべて「-0000」と同等であると見なされるべきです(SHOULD)。

Other multi-character (usually between 3 and 5) alphabetic time zones have been used in Internet messages. Any such time zone whose meaning is not known SHOULD be considered equivalent to "-0000" unless there is out-of-band information confirming their meaning.


4.4. Obsolete Addressing
4.4. 廃止されたアドレス指定

There are four primary differences in addressing. First, mailbox addresses were allowed to have a route portion before the addr-spec when enclosed in "<" and ">". The route is simply a comma-separated list of domain names, each preceded by "@", and the list terminated by a colon. Second, CFWS were allowed between the period-separated elements of local-part and domain (i.e., dot-atom was not used). In addition, local-part is allowed to contain quoted-string in addition to just atom. Third, mailbox-list and address-list were allowed to have "null" members. That is, there could be two or more commas in such a list with nothing in between them, or commas at the beginning or end of the list. Finally, US-ASCII control characters and quoted-pairs were allowed in domain literals and are added here.

アドレッシングには4つの主な違いがあります。まず、「<」と「>」で囲まれている場合、メールボックスアドレスはaddr-specの前にルート部分を持つことができました。ルートは、カンマで区切られたドメイン名のリストで、それぞれの前に「@」が付き、リストはコロンで終わります。第2に、ローカル部分とドメインのピリオドで区切られた要素の間でCFWSが許可されました(つまり、ドットアトムは使用されませんでした)。さらに、local-partには、atomだけでなくquoted-stringを含めることができます。 3番目に、メールボックスリストとアドレスリストには、 "null"メンバーを含めることができました。つまり、このようなリストには、間に何もないコンマが2つ以上あるか、リストの最初または最後にコンマが含まれている可能性があります。最後に、US-ASCII制御文字と引用符で囲まれたペアがドメインリテラルで許可され、ここに追加されます。

   obs-angle-addr  =   [CFWS] "<" obs-route addr-spec ">" [CFWS]

obs-route = obs-domain-list ":"

obs-route = obs-domain-list ":"

   obs-domain-list =   *(CFWS / ",") "@" domain
                       *("," [CFWS] ["@" domain])
   obs-mbox-list   =   *([CFWS] ",") mailbox *("," [mailbox / CFWS])
   obs-addr-list   =   *([CFWS] ",") address *("," [address / CFWS])

obs-group-list = 1*([CFWS] ",") [CFWS]

obs-group-list = 1 *([CFWS] "、")[CFWS]

obs-local-part = word *("." word)

obs-local-part = word *( "。" word)

obs-domain = atom *("." atom)

obs-domain = atom *( "。"アトム)

obs-dtext = obs-NO-WS-CTL / quoted-pair

obs-dtext = obs-NO-WS-CTL /引用ペア

When interpreting addresses, the route portion SHOULD be ignored.


4.5. Obsolete Header Fields
4.5. 廃止されたヘッダーフィールド

Syntactically, the primary difference in the obsolete field syntax is that it allows multiple occurrences of any of the fields and they may occur in any order. Also, any amount of white space is allowed before the ":" at the end of the field name.

構文的には、廃止されたフィールド構文の主な違いは、フィールドの複数の出現が可能であり、それらは任意の順序で出現する可能性があることです。また、フィールド名の最後の ":"の前に任意の量の空白を入れることができます。

obs-fields = *(obs-return / obs-received / obs-orig-date / obs-from / obs-sender / obs-reply-to / obs-to / obs-cc / obs-bcc / obs-message-id / obs-in-reply-to / obs-references / obs-subject / obs-comments / obs-keywords / obs-resent-date / obs-resent-from / obs-resent-send / obs-resent-rply / obs-resent-to / obs-resent-cc / obs-resent-bcc / obs-resent-mid / obs-optional)

obs-fields = *(obs-return / obs-received / obs-orig-date / obs-from / obs-sender / obs-reply-to / obs-to / obs-cc / obs-bcc / obs-message- id / obs-in-reply-to / obs-references / obs-subject / obs-comments / obs-keywords / obs-resent-date / obs-resent-from / obs-resent-send / obs-resent-rply / obs-resent-to / obs-resent-cc / obs-resent-bcc / obs-resent-mid / obs-optional)

Except for destination address fields (described in section 4.5.3), the interpretation of multiple occurrences of fields is unspecified. Also, the interpretation of trace fields and resent fields that do not occur in blocks prepended to the message is unspecified as well. Unless otherwise noted in the following sections, interpretation of other fields is identical to the interpretation of their non-obsolete counterparts in section 3.


4.5.1. Obsolete Origination Date Field
4.5.1. 廃止された開始日フィールド
   obs-orig-date   =   "Date" *WSP ":" date-time CRLF
4.5.2. Obsolete Originator Fields
4.5.2. 廃止された発信者フィールド
   obs-from        =   "From" *WSP ":" mailbox-list CRLF
   obs-sender      =   "Sender" *WSP ":" mailbox CRLF
   obs-reply-to    =   "Reply-To" *WSP ":" address-list CRLF
4.5.3. Obsolete Destination Address Fields
4.5.3. 廃止された宛先アドレスフィールド
   obs-to          =   "To" *WSP ":" address-list CRLF
   obs-cc          =   "Cc" *WSP ":" address-list CRLF
   obs-bcc         =   "Bcc" *WSP ":"
                       (address-list / (*([CFWS] ",") [CFWS])) CRLF

When multiple occurrences of destination address fields occur in a message, they SHOULD be treated as if the address list in the first occurrence of the field is combined with the address lists of the subsequent occurrences by adding a comma and concatenating.


4.5.4. Obsolete Identification Fields
4.5.4. 廃止された識別フィールド

The obsolete "In-Reply-To:" and "References:" fields differ from the current syntax in that they allow phrase (words or quoted strings) to appear. The obsolete forms of the left and right sides of msg-id allow interspersed CFWS, making them syntactically identical to local-part and domain, respectively.

廃止された「In-Reply-To:」フィールドと「References:」フィールドは、フレーズ(単語または引用符付き文字列)を表示できるという点で現在の構文とは異なります。 msg-idの左側と右側の廃止された形式により、CFWSを散在させることができ、それぞれ構文的にlocal-partとdomainと同じになります。

   obs-message-id  =   "Message-ID" *WSP ":" msg-id CRLF
   obs-in-reply-to =   "In-Reply-To" *WSP ":" *(phrase / msg-id) CRLF
   obs-references  =   "References" *WSP ":" *(phrase / msg-id) CRLF

obs-id-left = local-part

obs-id-left = local-part

obs-id-right = domain

obs-id-right =ドメイン

For purposes of interpretation, the phrases in the "In-Reply-To:" and "References:" fields are ignored.


Semantically, none of the optional CFWS in the local-part and the domain is part of the obs-id-left and obs-id-right, respectively.


4.5.5. Obsolete Informational Fields
4.5.5. 廃止された情報フィールド
   obs-subject     =   "Subject" *WSP ":" unstructured CRLF
   obs-comments    =   "Comments" *WSP ":" unstructured CRLF
   obs-keywords    =   "Keywords" *WSP ":" obs-phrase-list CRLF
4.5.6. Obsolete Resent Fields
4.5.6. 廃止された再送フィールド

The obsolete syntax adds a "Resent-Reply-To:" field, which consists of the field name, the optional comments and folding white space, the colon, and a comma separated list of addresses.


   obs-resent-from =   "Resent-From" *WSP ":" mailbox-list CRLF
   obs-resent-send =   "Resent-Sender" *WSP ":" mailbox CRLF
   obs-resent-date =   "Resent-Date" *WSP ":" date-time CRLF
   obs-resent-to   =   "Resent-To" *WSP ":" address-list CRLF
   obs-resent-cc   =   "Resent-Cc" *WSP ":" address-list CRLF
   obs-resent-bcc  =   "Resent-Bcc" *WSP ":"
                       (address-list / (*([CFWS] ",") [CFWS])) CRLF
   obs-resent-mid  =   "Resent-Message-ID" *WSP ":" msg-id CRLF
   obs-resent-rply =   "Resent-Reply-To" *WSP ":" address-list CRLF

As with other resent fields, the "Resent-Reply-To:" field is to be treated as trace information only.


4.5.7. Obsolete Trace Fields
4.5.7. 廃止されたトレースフィールド

The obs-return and obs-received are again given here as template definitions, just as return and received are in section 3. Their full syntax is given in [RFC5321].


   obs-return      =   "Return-Path" *WSP ":" path CRLF
   obs-received    =   "Received" *WSP ":" *received-token CRLF
4.5.8. Obsolete optional fields
4.5.8. 廃止されたオプションのフィールド
   obs-optional    =   field-name *WSP ":" unstructured CRLF
5. Security Considerations
5. セキュリティに関する考慮事項

Care needs to be taken when displaying messages on a terminal or terminal emulator. Powerful terminals may act on escape sequences and other combinations of US-ASCII control characters with a variety of consequences. They can remap the keyboard or permit other modifications to the terminal that could lead to denial of service or even damaged data. They can trigger (sometimes programmable) answerback messages that can allow a message to cause commands to be issued on the recipient's behalf. They can also affect the operation of terminal attached devices such as printers. Message viewers may wish to strip potentially dangerous terminal escape sequences from the message prior to display. However, other escape sequences appear in messages for useful purposes (cf. [ISO.2022.1994], [RFC2045], [RFC2046], [RFC2047], [RFC2049], [RFC4288], [RFC4289]) and therefore should not be stripped indiscriminately.


Transmission of non-text objects in messages raises additional security issues. These issues are discussed in [RFC2045], [RFC2046], [RFC2047], [RFC2049], [RFC4288], and [RFC4289].


Many implementations use the "Bcc:" (blind carbon copy) field, described in section 3.6.3, to facilitate sending messages to recipients without revealing the addresses of one or more of the addressees to the other recipients. Mishandling this use of "Bcc:" may disclose confidential information that could eventually lead to security problems through knowledge of even the existence of a particular mail address. For example, if using the first method described in section 3.6.3, where the "Bcc:" line is removed from the message, blind recipients have no explicit indication that they have been sent a blind copy, except insofar as their address does not appear in the header section of a message. Because of this, one of the blind addressees could potentially send a reply to all of the shown recipients and accidentally reveal that the message went to the blind recipient. When the second method from section 3.6.3 is used, the blind recipient's address appears in the "Bcc:" field of a separate copy of the message. If the "Bcc:" field sent contains all of the blind addressees, all of the "Bcc:" recipients will be seen by each "Bcc:" recipient. Even if a separate message is sent to each "Bcc:" recipient with only the individual's address, implementations still need to be careful to process replies to the message as per section 3.6.3 so as not to accidentally reveal the blind recipient to other recipients.

多くの実装では、セクション3.6.3で説明されている「Bcc:」(ブラインドカーボンコピー)フィールドを使用して、1つ以上の受信者のアドレスを他の受信者に明かさずに受信者にメッセージを送信できるようにします。この「Bcc:」の使い方を誤ると、特定のメールアドレスの存在さえ知ることによって、最終的にはセキュリティの問題につながる可能性のある機密情報が開示される可能性があります。たとえば、セクション3.6.3で説明されている「Bcc:」行がメッセージから削除されている最初の方法を使用する場合、ブラインド受信者は、アドレスがない限りを除いて、ブラインドコピーが送信されたことを明示的に示しません。メッセージのヘッダーセクションに表示されます。このため、ブラインドアドレスの1つが、表示されたすべての受信者に返信を送信し、メッセージがブラインド受信者に送信されたことを誤って明らかにする可能性があります。セクション3.6.3の2番目の方法を使用すると、メッセージの別のコピーの「Bcc:」フィールドにブラインド受信者のアドレスが表示されます。送信された「Bcc:」フィールドにすべてのブラインドアドレスが含まれている場合、すべての「Bcc:」受信者は各「Bcc:」受信者に表示されます。個別のメッセージが各 "Bcc:"受信者に送信され、個人のアドレスのみが送信される場合でも、実装は、セクション3.6.3に従ってメッセージへの返信を処理するように注意する必要があります。 。

6. IANA Considerations
6. IANAに関する考慮事項

This document updates the registrations that appeared in [RFC4021] that referred to the definitions in [RFC2822]. IANA has updated the Permanent Message Header Field Repository with the following header fields, in accordance with the procedures set out in [RFC3864].

このドキュメントは、[RFC2822]の定義を参照する[RFC4021]に現れた登録を更新します。 IANAは、[RFC3864]で説明されている手順に従って、次のヘッダーフィールドで永続メッセージヘッダーフィールドリポジトリを更新しました。

   Header field name:  Date
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.1)
   Header field name:  From
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.2)
   Header field name:  Sender
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.2)
   Header field name:  Reply-To
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.2)
   Header field name:  To
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.3)
   Header field name:  Cc
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.3)
   Header field name:  Bcc
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.3)
   Header field name:  Message-ID
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.4)
   Header field name:  In-Reply-To
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.4)
   Header field name:  References
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.4)
   Header field name:  Subject
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.5)
   Header field name:  Comments
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.5)
   Header field name:  Keywords
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.5)
   Header field name:  Resent-Date
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.6)
   Header field name:  Resent-From
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.6)
   Header field name:  Resent-Sender
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.6)
   Header field name:  Resent-To
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.6)
   Header field name:  Resent-Cc
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.6)
   Header field name:  Resent-Bcc
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.6)
   Header field name:  Resent-Reply-To
   Applicable protocol:  Mail
   Status:  obsolete
   Author/Change controller:  IETF
   Specification document(s):  This document (section 4.5.6)
   Header field name:  Resent-Message-ID
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.6)
   Header field name:  Return-Path
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.7)
   Header field name:  Received
   Applicable protocol:  Mail
   Status:  standard
   Author/Change controller:  IETF
   Specification document(s):  This document (section 3.6.7)
   Related information:  [RFC5321]
Appendix A. Example Messages

This section presents a selection of messages. These are intended to assist in the implementation of this specification, but should not be taken as normative; that is to say, although the examples in this section were carefully reviewed, if there happens to be a conflict between these examples and the syntax described in sections 3 and 4 of this document, the syntax in those sections is to be taken as correct.


   In the text version of this document, messages in this section are
   delimited between lines of "----".  The "----" lines are not part of
   the message itself.

Appendix A.1. Addressing Examples


The following are examples of messages that might be sent between two individuals.


Appendix A.1.1. A Message from One Person to Another with Simple Addressing


This could be called a canonical message. It has a single author, John Doe, a single recipient, Mary Smith, a subject, the date, a message identifier, and a textual message in the body.

これは、正規のメッセージと呼ぶことができます。本文には、1人の著者、John Doe、1人の受信者、Mary Smith、件名、日付、メッセージ識別子、およびテキストメッセージが含まれています。

   From: John Doe <jdoe@machine.example>
   To: Mary Smith <>
   Subject: Saying Hello
   Date: Fri, 21 Nov 1997 09:55:06 -0600
   Message-ID: <1234@local.machine.example>
   This is a message just to say hello.
   So, "Hello".

If John's secretary Michael actually sent the message, even though John was the author and replies to this message should go back to him, the sender field would be used:


   From: John Doe <jdoe@machine.example>
   Sender: Michael Jones <mjones@machine.example>
   To: Mary Smith <>
   Subject: Saying Hello
   Date: Fri, 21 Nov 1997 09:55:06 -0600
   Message-ID: <1234@local.machine.example>
   This is a message just to say hello.
   So, "Hello".

Appendix A.1.2. Different Types of Mailboxes


This message includes multiple addresses in the destination fields and also uses several different forms of addresses.


   From: "Joe Q. Public" <>
   To: Mary Smith <mary@x.test>,, Who? <one@y.test>
   Cc: <boss@nil.test>, "Giant; \"Big\" Box" <>
   Date: Tue, 1 Jul 2003 10:52:37 +0200
   Message-ID: <>
   Hi everyone.

Note that the display names for Joe Q. Public and Giant; "Big" Box needed to be enclosed in double-quotes because the former contains the period and the latter contains both semicolon and double-quote characters (the double-quote characters appearing as quoted-pair constructs). Conversely, the display name for Who? could appear without them because the question mark is legal in an atom. Notice also that and boss@nil.test have no display names associated with them at all, and uses the simpler address form without the angle brackets.

Joe Q. PublicおよびGiantの表示名に注意してください。前者にはピリオドが含まれ、後者にはセミコロンと二重引用符の文字(二重引用符は引用符で囲まれたペアのコンストラクトとして表示される)の両方が含まれるため、「ビッグ」ボックスは二重引用符で囲む必要がありました。逆に、誰の表示名ですか?疑問符はアトムで合法であるため、それらなしで表示できます。また、jdoe @ example.orgとboss@nil.testには表示名がまったく関連付けられておらず、jdoe @ example.orgは山かっこなしの単純なアドレス形式を使用していることにも注意してください。

Appendix A.1.3. Group Addresses


   From: Pete <pete@silly.example>
   To: A Group:Ed Jones <c@a.test>,joe@where.test,John <jdoe@one.test>;
   Cc: Undisclosed recipients:;
   Date: Thu, 13 Feb 1969 23:32:54 -0330
   Message-ID: <testabcd.1234@silly.example>

In this message, the "To:" field has a single group recipient named "A Group", which contains 3 addresses, and a "Cc:" field with an empty group recipient named Undisclosed recipients.

このメッセージの「To:」フィールドには、「A Group」という名前の単一のグループ受信者があり、3つのアドレスが含まれています。「Cc:」フィールドには、Undisclosed recipientsという名前の空のグループ受信者がいます。

Appendix A.2. Reply Messages


The following is a series of three messages that make up a conversation thread between John and Mary. John first sends a message to Mary, Mary then replies to John's message, and then John replies to Mary's reply message.


Note especially the "Message-ID:", "References:", and "In-Reply-To:" fields in each message.


   From: John Doe <jdoe@machine.example>
   To: Mary Smith <>
   Subject: Saying Hello
   Date: Fri, 21 Nov 1997 09:55:06 -0600
   Message-ID: <1234@local.machine.example>
   This is a message just to say hello.
   So, "Hello".

When sending replies, the Subject field is often retained, though prepended with "Re: " as described in section 3.6.5.


   From: Mary Smith <>
   To: John Doe <jdoe@machine.example>
   Reply-To: "Mary Smith: Personal Account" <smith@home.example>
   Subject: Re: Saying Hello
   Date: Fri, 21 Nov 1997 10:01:10 -0600
   Message-ID: <>
   In-Reply-To: <1234@local.machine.example>
   References: <1234@local.machine.example>
   This is a reply to your hello.

Note the "Reply-To:" field in the above message. When John replies to Mary's message above, the reply should go to the address in the "Reply-To:" field instead of the address in the "From:" field.


   To: "Mary Smith: Personal Account" <smith@home.example>
   From: John Doe <jdoe@machine.example>
   Subject: Re: Saying Hello
   Date: Fri, 21 Nov 1997 11:00:00 -0600
   Message-ID: <abcd.1234@local.machine.test>
   In-Reply-To: <>
   References: <1234@local.machine.example> <>
   This is a reply to your reply.

Appendix A.3. Resent Messages


Start with the message that has been used as an example several times:


   From: John Doe <jdoe@machine.example>
   To: Mary Smith <>
   Subject: Saying Hello
   Date: Fri, 21 Nov 1997 09:55:06 -0600
   Message-ID: <1234@local.machine.example>
   This is a message just to say hello.
   So, "Hello".

Say that Mary, upon receiving this message, wishes to send a copy of the message to Jane such that (a) the message would appear to have come straight from John; (b) if Jane replies to the message, the reply should go back to John; and (c) all of the original information, like the date the message was originally sent to Mary, the message identifier, and the original addressee, is preserved. In this case, resent fields are prepended to the message:

メアリーがこのメッセージを受信したら、次のようにメッセージのコピーをジェーンに送信したいとします。(a)メッセージがジョンから直接届いたように見える。 (b)ジェーンがメッセージに返信する場合、返信はジョンに戻る必要があります。 (c)メッセージが最初にメアリーに送信された日付、メッセージ識別子、および元の受信者などの元の情報はすべて保持されます。この場合、再送フィールドがメッセージの前に追加されます。

   Resent-From: Mary Smith <>
   Resent-To: Jane Brown <j-brown@other.example>
   Resent-Date: Mon, 24 Nov 1997 14:22:01 -0800
   Resent-Message-ID: <>
   From: John Doe <jdoe@machine.example>
   To: Mary Smith <>
   Subject: Saying Hello
   Date: Fri, 21 Nov 1997 09:55:06 -0600
   Message-ID: <1234@local.machine.example>
   This is a message just to say hello.
   So, "Hello".

If Jane, in turn, wished to resend this message to another person, she would prepend her own set of resent header fields to the above and send that. (Note that for brevity, trace fields are not shown.)

次に、Janeがこのメッセージを別の人に再送信したい場合は、再送信したヘッダーフィールドのセットを上記の先頭に追加して送信します。 (簡潔にするために、トレースフィールドは表示されないことに注意してください。)

Appendix A.4. Messages with Trace Fields


As messages are sent through the transport system as described in [RFC5321], trace fields are prepended to the message. The following is an example of what those trace fields might look like. Note that there is some folding white space in the first one since these lines can be long.


   Received: from x.y.test
      via TCP
      with ESMTP
      id ABC12345
      for <>;  21 Nov 1997 10:05:43 -0600
   Received: from node.example by x.y.test; 21 Nov 1997 10:01:22 -0600
   From: John Doe <jdoe@node.example>
   To: Mary Smith <>
   Subject: Saying Hello
   Date: Fri, 21 Nov 1997 09:55:06 -0600
   Message-ID: <1234@local.node.example>
   This is a message just to say hello.
   So, "Hello".

Appendix A.5. White Space, Comments, and Other Oddities


White space, including folding white space, and comments can be inserted between many of the tokens of fields. Taking the example from A.1.3, white space and comments can be inserted into all of the fields.

空白(折りたたみ空白を含む)とコメントは、フィールドの多くのトークンの間に挿入できます。 A.1.3の例では、空白とコメントをすべてのフィールドに挿入できます。

   From: Pete(A nice \) chap) <pete(his account)@silly.test(his host)>
   To:A Group(Some people)
        :Chris Jones <c@(Chris's host.)public.example>,
     John <jdoe@one.test> (my dear friend); (the end of the group)
   Cc:(Empty list)(start)Hidden recipients  :(nobody(that I know))  ;
   Date: Thu,
                  -0330 (Newfoundland Time)
   Message-ID:              <testabcd.1234@silly.test>

The above example is aesthetically displeasing, but perfectly legal. Note particularly (1) the comments in the "From:" field (including one that has a ")" character appearing as part of a quoted-pair); (2) the white space absent after the ":" in the "To:" field as well as the comment and folding white space after the group name, the special character (".") in the comment in Chris Jones's address, and the folding white space before and after ","; (3) the multiple and nested comments in the "Cc:" field as well as the comment immediately following the ":" after "Cc"; (4) the folding white space (but no comments except at the end) and the missing seconds in the time of the date field; and (5) the white space before (but not within) the identifier in the "Message-ID:" field.

上記の例は見た目が悪いですが、完全に合法です。特に、(1)「From:」フィールドのコメント(引用符で囲まれたペアの一部として表示される「)」文字を含むコメントに注意してください。 (2)「To:」フィールドの「:」の後に空白、およびグループ名の後のコメントと折りたたみ空白、クリス・ジョーンズのアドレスのコメントの特殊文字(「。」)、および「」の前後の折りたたみ空白。 (3)「Cc:」フィールド内の複数のネストされたコメント、および「Cc」の後の「:」の直後のコメント。 (4)折りたたみ式の空白スペース(ただし、最後以外にコメントはありません)および日付フィールドの時刻の欠落秒。 (5)「Message-ID:」フィールドの識別子の前にある(ただし、識別子内にない)空白。

Appendix A.6. Obsoleted Forms


The following are examples of obsolete (that is, the "MUST NOT generate") syntactic elements described in section 4 of this document.


Appendix A.6.1. Obsolete Addressing


Note in the example below the lack of quotes around Joe Q. Public, the route that appears in the address for Mary Smith, the two commas that appear in the "To:" field, and the spaces that appear around the "." in the jdoe address.

下の例では、Joe Q. Public、Mary Smithのアドレスに表示されるルート、[To:]フィールドに表示される2つのコンマ、および "。"の周囲にあるスペースを引用符で囲んでいないことに注意してください。 jdoeアドレス。

   From: Joe Q. Public <>
   To: Mary Smith <>, , jdoe@test  . example
   Date: Tue, 1 Jul 2003 10:52:37 +0200
   Message-ID: <>
   Hi everyone.

Appendix A.6.2. Obsolete Dates


The following message uses an obsolete date format, including a non-numeric time zone and a two digit year. Note that although the day-of-week is missing, that is not specific to the obsolete syntax; it is optional in the current syntax as well.


   From: John Doe <jdoe@machine.example>
   To: Mary Smith <>
   Subject: Saying Hello
   Date: 21 Nov 97 09:55:06 GMT
   Message-ID: <1234@local.machine.example>
   This is a message just to say hello.
   So, "Hello".

Appendix A.6.3. Obsolete White Space and Comments


White space and comments can appear between many more elements than in the current syntax. Also, folding lines that are made up entirely of white space are legal.


   From  : John Doe <jdoe@machine(comment).  example>
   To    : Mary Smith
   Subject     : Saying Hello
   Date  : Fri, 21 Nov 1997 09(comment):   55  :  06 -0600
   Message-ID  : <1234   @   local(blah)  .machine .example>
   This is a message just to say hello.
   So, "Hello".
   Note especially the second line of the "To:" field.  It starts with
   two space characters.  (Note that "__" represent blank spaces.)
   Therefore, it is considered part of the folding, as described in
   section 4.2.  Also, the comments and white space throughout
   addresses, dates, and message identifiers are all part of the
   obsolete syntax.
Appendix B. Differences from Earlier Specifications

This appendix contains a list of changes that have been made in the Internet Message Format from earlier specifications, specifically [RFC0822], [RFC1123], and [RFC2822]. Items marked with an asterisk (*) below are items which appear in section 4 of this document and therefore can no longer be generated.


The following are the changes made from [RFC0822] and [RFC1123] to [RFC2822] that remain in this document:


1. Period allowed in obsolete form of phrase. 2. ABNF moved out of document, now in [RFC5234]. 3. Four or more digits allowed for year. 4. Header field ordering (and lack thereof) made explicit. 5. Encrypted header field removed. 6. Specifically allow and give meaning to "-0000" time zone. 7. Folding white space is not allowed between every token. 8. Requirement for destinations removed. 9. Forwarding and resending redefined. 10. Extension header fields no longer specifically called out. 11. ASCII 0 (null) removed.* 12. Folding continuation lines cannot contain only white space.* 13. Free insertion of comments not allowed in date.* 14. Non-numeric time zones not allowed.* 15. Two digit years not allowed.* 16. Three digit years interpreted, but not allowed for generation.* 17. Routes in addresses not allowed.* 18. CFWS within local-parts and domains not allowed.* 19. Empty members of address lists not allowed.* 20. Folding white space between field name and colon not allowed.* 21. Comments between field name and colon not allowed. 22. Tightened syntax of in-reply-to and references.* 23. CFWS within msg-id not allowed.* 24. Tightened semantics of resent fields as informational only. 25. Resent-Reply-To not allowed.* 26. No multiple occurrences of fields (except resent and received).* 27. Free CR and LF not allowed.* 28. Line length limits specified. 29. Bcc more clearly specified.

1. 時代遅れのフレーズ形式で許可された期間。 2. ABNFはドキュメントの外に移動しました。現在は[RFC5234]にあります。 3.年には4桁以上を使用できます。 4.ヘッダーフィールドの順序(およびその欠如)が明示的になりました。 5.暗号化されたヘッダーフィールドが削除されました。 6. "-0000"タイムゾーンに具体的に許可し、意味を与えます。 7.すべてのトークンの間で空白を折りたたむことはできません。 8.宛先の要件が削除されました。 9.転送と再送信が再定義されました。 10.拡張ヘッダーフィールドが明確に呼び出されなくなりました。 11. ASCII 0(ヌル)は削除されました。* 12.折りたたみ継続行には空白のみを含めることはできません。* 13.日付にコメントを自由に挿入することはできません。* 14.非数値のタイムゾーンは許可されません。* 15. 2桁の年許可されません。* 16. 3桁の年は解釈されますが、生成は許可されません。* 17.アドレス内のルートは許可されません。* 18.ローカルパーツおよびドメイン内のCFWSは許可されません。* 19.アドレスリストの空のメンバーは許可されません。 * 20.フィールド名とコロンの間の空白の折り返しは許可されません。* 21.フィールド名とコロンの間のコメントは許可されません。 22. in-reply-toとreferenceの構文が強化されました。* 23. msg-id内のCFWSは許可されません。* 24.再送信されたフィールドのセマンティクスが情報としてのみ強化されました。 25. Resent-Reply-Toは許可されません。* 26.複数のフィールドの出現はありません(再送信および受信を除く)。* 27.無料のCRおよびLFは許可されません。* 28.行の長さの制限が指定されました。 29.より明確に指定されたBcc。

The following are changes from [RFC2822]. 1. Assorted typographical/grammatical errors fixed and clarifications made. 2. Changed "standard" to "document" or "specification" throughout. 3. Made distinction between "header field" and "header section". 4. Removed NO-WS-CTL from ctext, qtext, dtext, and unstructured.* 5. Moved discussion of specials to the "Atom" section. Moved text to "Overall message syntax" section. 6. Simplified CFWS syntax. 7. Fixed unstructured syntax. 8. Changed date and time syntax to deal with white space in obsolete date syntax. 9. Removed quoted-pair from domain literals and message identifiers.* 10. Clarified that other specifications limit domain syntax. 11. Simplified "Bcc:" and "Resent-Bcc:" syntax. 12. Allowed optional-field to appear within trace information. 13. Removed no-fold-quote from msg-id. Clarified syntax limitations. 14. Generalized "Received:" syntax to fix bugs and move definition out of this document. 15. Simplified obs-qp. Fixed and simplified obs-utext (which now only appears in the obsolete syntax). Removed obs-text and obs-char, adding obs-body. 16. Fixed obsolete date syntax to allow for more (or less) comments and white space. 17. Fixed all obsolete list syntax (obs-domain-list, obs-mbox-list, obs-addr-list, obs-phrase-list, and the newly added obs-group-list). 18. Fixed obs-reply-to syntax. 19. Fixed obs-bcc and obs-resent-bcc to allow empty lists. 20. Removed obs-path.

以下は、[RFC2822]からの変更点です。 1.さまざまな誤植/文法エラーが修正され、明確化が行われました。 2.「標準」を「ドキュメント」または「仕様」に変更。 3.「ヘッダーフィールド」と「ヘッダーセクション」を区別しました。 4. ctext、qtext、dtext、および非構造化からNO-WS-CTLを削除しました。* 5.スペシャルの説明を「Atom」セクションに移動しました。テキストを「全体的なメッセージ構文」セクションに移動しました。 6.簡略化されたCFWS構文。 7.非構造化構文を修正しました。 8.日付と時刻の構文を変更して、廃止された日付構文の空白を処理します。 9.ドメインリテラルとメッセージ識別子から引用符で囲まれたペアを削除しました。* 10.他の仕様がドメイン構文を制限することを明確にしました。 11.簡略化された「Bcc:」および「Resent-Bcc:」構文。 12. optional-fieldをトレース情報内に表示できるようになりました。 13. msg-idからno-fold-quoteを削除しました。構文の制限を明確にしました。 14.バグを修正し、このドキュメントから定義を移動するための「Received:」構文の一般化。 15. obs-qpの簡略化。修正および簡略化されたobs-utext(現在は廃止された構文でのみ表示されます)。 obs-textとobs-charが削除され、obs-bodyが追加されました。 16.廃止された日付の構文を修正して、コメントを増やしたり減らしたりして、空白を追加できるようにしました。 17.すべての廃止されたリスト構文(obs-domain-list、obs-mbox-list、obs-addr-list、obs-phrase-list、および新しく追加されたobs-group-list)を修正しました。 18. obs-reply-to構文を修正しました。 19. obs-bccおよびobs-resent-bccが空のリストを許可するように修正されました。 20. obs-pathを削除しました。

Appendix C. Acknowledgements

Many people contributed to this document. They included folks who participated in the Detailed Revision and Update of Messaging Standards (DRUMS) Working Group of the Internet Engineering Task Force (IETF), the chair of DRUMS, the Area Directors of the IETF, and people who simply sent their comments in via email. The editor is deeply indebted to them all and thanks them sincerely. The below list includes everyone who sent email concerning both this document and [RFC2822]. Hopefully, everyone who contributed is named here:


   | Matti Aarnio       | Tanaka Akira         | Russ Allbery        |
   | Eric Allman        | Harald Alvestrand    | Ran Atkinson        |
   | Jos Backus         | Bruce Balden         | Dave Barr           |
   | Alan Barrett       | John Beck            | J Robert von Behren |
   | Jos den Bekker     | D J Bernstein        | James Berriman      |
   | Oliver Block       | Norbert Bollow       | Raj Bose            |
   | Antony Bowesman    | Scott Bradner        | Randy Bush          |
   | Tom Byrer          | Bruce Campbell       | Larry Campbell      |
   | W J Carpenter      | Michael Chapman      | Richard Clayton     |
   | Maurizio Codogno   | Jim Conklin          | R Kelley Cook       |
   | Nathan Coulter     | Steve Coya           | Mark Crispin        |
   | Dave Crocker       | Matt Curtin          | Michael D'Errico    |
   | Cyrus Daboo        | Michael D Dean       | Jutta Degener       |
   | Mark Delany        | Steve Dorner         | Harold A Driscoll   |
   | Michael Elkins     | Frank Ellerman       | Robert Elz          |
   | Johnny Eriksson    | Erik E Fair          | Roger Fajman        |
   | Patrik Faltstrom   | Claus Andre Faerber  | Barry Finkel        |
   | Erik Forsberg      | Chuck Foster         | Paul Fox            |
   | Klaus M Frank      | Ned Freed            | Jochen Friedrich    |
   | Randall C Gellens  | Sukvinder Singh Gill | Tim Goodwin         |
   | Philip Guenther    | Arnt Gulbrandsen     | Eric A Hall         |
   | Tony Hansen        | John Hawkinson       | Philip Hazel        |
   | Kai Henningsen     | Robert Herriot       | Paul Hethmon        |
   | Jim Hill           | Alfred Hoenes        | Paul E Hoffman      |
   | Steve Hole         | Kari Hurtta          | Marco S Hyman       |
   | Ofer Inbar         | Olle Jarnefors       | Kevin Johnson       |
   | Sudish Joseph      | Maynard Kang         | Prabhat Keni        |
   | John C Klensin     | Graham Klyne         | Brad Knowles        |
   | Shuhei Kobayashi   | Peter Koch           | Dan Kohn            |
   | Christian Kuhtz    | Anand Kumria         | Steen Larsen        |
   | Eliot Lear         | Barry Leiba          | Jay Levitt          |
   | Bruce Lilly        | Lars-Johan Liman     | Charles Lindsey     |
   | Pete Loshin        | Simon Lyall          | Bill Manning        |
   | John Martin        | Mark Martinec        | Larry Masinter      |
   | Denis McKeon       | William P McQuillan  | Alexey Melnikov     |
   | Perry E Metzger    | Steven Miller        | S Moonesamy         |
   | Keith Moore        | John Gardiner Myers  | Chris Newman        |
   | John W Noerenberg  | Eric Norman          | Mike O'Dell         |
   | Larry Osterman     | Paul Overell         | Jacob Palme         |
   | Michael A Patton   | Uzi Paz              | Michael A Quinlan   |
   | Robert Rapplean    | Eric S Raymond       | Sam Roberts         |
   | Hugh Sasse         | Bart Schaefer        | Tom Scola           |
   | Wolfgang Segmuller | Nick Shelness        | John Stanley        |
   | Einar Stefferud    | Jeff Stephenson      | Bernard Stern       |
   | Peter Sylvester    | Mark Symons          | Eric Thomas         |
   | Lee Thompson       | Karel De Vriendt     | Matthew Wall        |
   | Rolf Weber         | Brent B Welch        | Dan Wing            |
   | Jack De Winter     | Gregory J Woodhouse  | Greg A Woods        |
   | Kazu Yamamoto      | Alain Zahm           | Jamie Zawinski      |
   | Timothy S Zurcher  |                      |                     |
7. References
7. 参考文献
7.1. Normative References
7.1. 引用文献

[ANSI.X3-4.1986] American National Standards Institute, "Coded Character Set - 7-bit American Standard Code for Information Interchange", ANSI X3.4, 1986.

[ANSI.X3-4.1986] American National Standards Institute、「Coded Character Set-7-bit American Standard Code for Information Interchange」、ANSI X3.4、1986。

[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, November 1987.

[RFC1034] Mockapetris、P。、「ドメイン名-概念と機能」、STD 13、RFC 1034、1987年11月。

[RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987.

[RFC1035] Mockapetris、P。、「ドメイン名-実装と仕様」、STD 13、RFC 1035、1987年11月。

[RFC1123] Braden, R., "Requirements for Internet Hosts - Application and Support", STD 3, RFC 1123, October 1989.

[RFC1123] Braden、R。、「インターネットホストの要件-アプリケーションとサポート」、STD 3、RFC 1123、1989年10月。

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2119] Bradner、S。、「要件レベルを示すためにRFCで使用するキーワード」、BCP 14、RFC 2119、1997年3月。

[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008.

[RFC5234] Crocker、D。およびP. Overell、「構文仕様の拡張BNF:ABNF」、STD 68、RFC 5234、2008年1月。

7.2. Informative References
7.2. 参考引用

[RFC0822] Crocker, D., "Standard for the format of ARPA Internet text messages", STD 11, RFC 822, August 1982.

[RFC0822]クロッカーD。、「ARPAインターネットテキストメッセージのフォーマットの標準」、STD 11、RFC 822、1982年8月。

[RFC1305] Mills, D., "Network Time Protocol (Version 3) Specification, Implementation", RFC 1305, March 1992.

[RFC1305] Mills、D。、「Network Time Protocol(Version 3)Specification、Implementation」、RFC 1305、1992年3月。

[ISO.2022.1994] International Organization for Standardization, "Information technology - Character code structure and extension techniques", ISO Standard 2022, 1994.


[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996.

[RFC2045] Freed、N。およびN. Borenstein、「Multipurpose Internet Mail Extensions(MIME)Part One:Format of Internet Message Bodies」、RFC 2045、1996年11月。

[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996.

[RFC2046] Freed、N。およびN. Borenstein、「Multipurpose Internet Mail Extensions(MIME)Part Two:Media Types」、RFC 2046、1996年11月。

[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text", RFC 2047, November 1996.

[RFC2047]ムーアK。、「MIME(多目的インターネットメール拡張)パート3:非ASCIIテキストのメッセージヘッダー拡張」、RFC 2047、1996年11月。

[RFC2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples", RFC 2049, November 1996.

[RFC2049] Freed、N。およびN. Borenstein、「Multipurpose Internet Mail Extensions(MIME)Part Five:Conformance Criteria and Examples」、RFC 2049、1996年11月。

[RFC2822] Resnick, P., "Internet Message Format", RFC 2822, April 2001.

[RFC2822] Resnick、P。、「インターネットメッセージ形式」、RFC 2822、2001年4月。

[RFC3864] Klyne, G., Nottingham, M., and J. Mogul, "Registration Procedures for Message Header Fields", BCP 90, RFC 3864, September 2004.

[RFC3864]クライン、G。、ノッティンガム、M。、およびJ.モーグル、「メッセージヘッダーフィールドの登録手順」、BCP 90、RFC 3864、2004年9月。

[RFC4021] Klyne, G. and J. Palme, "Registration of Mail and MIME Header Fields", RFC 4021, March 2005.

[RFC4021] Klyne, G. and J. Palme, "Registration of Mail and MIME Header Fields", RFC 4021, March 2005.

[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and Registration Procedures", BCP 13, RFC 4288, December 2005.

[RFC4288] Freed、N。およびJ. Klensin、「Media Type Specifications and Registration Procedures」、BCP 13、RFC 4288、2005年12月。

[RFC4289] Freed, N. and J. Klensin, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", BCP 13, RFC 4289, December 2005.

[RFC4289] Freed、N。およびJ. Klensin、「Multipurpose Internet Mail Extensions(MIME)Part Four:Registration Procedures」、BCP 13、RFC 4289、2005年12月。

[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, October 2008.

[RFC5321] Klensin、J。、「Simple Mail Transfer Protocol」、RFC 5321、2008年10月。

Author's Address


Peter W. Resnick (editor) Qualcomm Incorporated 5775 Morehouse Drive San Diego, CA 92121-1714 US

ピーターW.レズニック(編集者)Qualcomm Incorporated 5775 Morehouse Drive San Diego、CA 92121-1714 US

   Phone: +1 858 651 4478
   URI: Full Copyright Statement

Copyright (C) The IETF Trust (2008).

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