2. Requesting Message Disposition Notifications

Message disposition notifications are requested by including a Disposition-Notification-To header in the message. Further information to be used by the recipient's MUA in generating the MDN may be provided by also including Original-Recipient and/or Disposition-Notification-Options headers in the message.

メッセージ配置通知はメッセージに Disposition-Notification-To 頭を含めることにより要求します。受信者の MUA が MDN を生成するに当たって使用する更なる情報をメッセージの Original-Recipient 頭や Disposition-Notification-Option]] 頭も含めることにより提供しても構いません。

2.1. The Disposition-Notification-To Header

A request that for the receiving user agent to issue message disposition notifications is made by placing a Disposition-Notification-To header into the message. The syntax of the header, using the ABNF of RFC 822 [2], is

受信した利用者エージェントがメッセージ配置通知を発行するようにとの要求はメッセージに Disposition-Notification-To 頭を入れることにより行います。 この頭の構文は次の通りです。

• mdn-request-header = "Disposition-Notification-To" ":" 1#mailbox mailbox *("," mailbox)

The presence of a Disposition-Notification-To header in a message is merely a request for an MDN. The recipients' user agents are always free to silently ignore such a request. Alternatively, an explicit denial of the request for information about the disposition of the message may be sent using the "denied" disposition in an MDN.

メッセージにおける Disposition-Notification-To 頭の存在は単なる MDN の要求です。 受信者の利用者エージェントはこの要求を常に黙って自由に無視できます。 その代わりに MDN の denied 配置を使ってメッセージの配置に関する情報の要求の拒絶を明示的に送信しても構いません。

An MDN MUST NOT itself have a Disposition-Notification-To header. An MDN MUST NOT be generated in response to an MDN.

MDN 自体は Disposition-Notigication-To 頭を持っていてはなりません。 MDN を MDN への応答として生成してはなりません。

At most one MDN may be issued on behalf of each particular recipient by their user agent. A user agent MUST NOT issue more than one MDN on behalf of each particular recipient. That is, once an MDN has been issued on behalf of a recipient, no further MDNs may be issued on behalf of that recipient, even if another disposition is performed on the message. However, if a message is forwarded, an MDN may have been issued for the recipient doing the forwarding and the recipient of the forwarded message may also cause an MDN to be generated.

利用者エージェントはそれぞれの受信者について複数回 MDN を発行してはなりません。つまり、ある受信者について1度 MDN が発行されたら、以後そのメッセージに別の配置が取られたとしても MDN をその受信者について再度発行してはいけません。 但し、メッセージが転送された場合は転送を行った受信者について MDN を発行しても構いませんし、転送メッセージの受信者も MDN を生成して構いません。

While Internet standards normally do not specify the behavior of user interfaces, it is strongly recommended that the user agent obtain the user's consent before sending an MDN. This consent could be obtained for each message through some sort of prompt or dialog box, or globally through the user's setting of a preference. The user might also indicate globally that MDNs are to never to be sent or that a "denied" MDN is always sent in response to a request for an MDN.

インターネット規格は通常利用者界面の動作を規定しませんが、 利用者エージェントは MDN を送信する前に利用者の同意を得ることを強く推奨します。 この同意は問合せや対話箱のようなもので得ることもできましょうし、 利用者の設定であらかじめ得ておくことも可能でしょう。 利用者は MDN を絶対に送らないことや denied MDN を常に MDN 要求に対する応答として送信することを望むかもしれません。

MDNs SHOULD NOT be sent automatically if the address in the Disposition-Notification-To header differs from the address in the Return-Path header (see RFC 822 [2] [RFC-MSGFMT] ). In this case, confirmation from the user SHOULD be obtained, if possible. If obtaining consent is not possible (e.g., because the user is not online at the time), then an MDN SHOULD NOT be sent.

Disposition-Notification-To 頭の番地が Return-Path 頭の番地と異なる場合には MDN を自動的に送信するべきではありません。こも場合、 可能なら利用者に確認するべきです。同意を得ることが不可能な場合 (例えば利用者がその時線上でない場合) は MDN を送るべきではありません。

Confirmation from the user SHOULD be obtained (or no MDN sent) if there is no Return-Path header in the message, or if there is more than one distinct address in the Disposition-Notification-To header.

メッセージに Return-Path 頭がない場合や Disposition-Notification-To 頭に複数の異なる番地が指定されている場合には利用者に確認を取る (か MDN を送らない) べきです。

The comparison of the addresses should be done using only the addr-spec (local-part "@" domain) portion, excluding any phrase and route. The comparison MUST be case-sensitive for the local-part and case-insensitive for the domain part.

番地の比較は addr-spec (local-part @" domain) の部分のみで phrase や route は除外して行うべきです。比較は local-part は大文字・小文字を区別し、 domain 部は大文字・ 小文字を区別せずに行わなければなりません。

If the message contains more than one Return-Path header, the implementation may pick one to use for the comparison, or treat the situation as a failure of the comparison.

メッセージが複数 Return-Path 頭を持っている場合、実装は比較時にどれか1つを選んでも構いませんし、 比較失敗としても構いません。

The reason for not automatically sending an MDN if the comparison fails or more than one address is specified is to reduce the possibilities for mail loops and use of MDNs possibility of mail loops and of MDNs being used for mail bombing.

比較失敗時や複数の番地が指定された時に自動的に送信するべきではないのは、 メイルの循環や MDN がメイル爆弾に使われる危険性を減らすためです。

A message that contains a Disposition-Notification-To header SHOULD also contain a Message-ID header as specified in RFC 822 [2] [RFC-MSGFMT] . This will permit automatic correlation of MDNs with their original messages by user agents.

Disposition-Notification-To 頭を含むメッセージは、 RFC 2822 で規定されている Message-ID 頭も含むべきです。そうすれば利用者エージェントは MDN と元のメッセージを自動的に関係づけられます。

If it is desired to the request for message disposition notifications for some recipients and not others is desired, two copies of the message should be sent, one with an Disposition-Notification-To header and one without. Many of the other headers of the message (e.g., To, cc Cc) will be the same in both copies. The recipients in the respective message envelopes determine for whom message disposition notifications are requested and for whom they are not. If desired, the Message-ID header may be the same in both copies of the message. Note that there are other situations (e.g., bcc Bcc) in which it is necessary to send multiple copies of a message with slightly different headers. The combination of such situations and the need to request MDNs for a subset of all recipients may result in more than two copies of a message being sent, some with a Disposition-Notification-To header and some without.

受信者の一部にはメッセージ配置通知を要求し、他の受信者には要求したくない時は、 Disposition-Notification-To 頭があるものとないものの 2種類を用意して送信するべきです。メッセージの他の多くの頭 (例えば To や Cc は両者共同じにします。 各メッセージの封筒にはそれぞれメッセージ配置通知を要求する受信者と要求しない受信者を指定します。 それが望ましければ両メッセージ共 Message-ID 頭は同じにしても構いません。ちなみに、他にも頭が幾分異なるメッセージを複数送信するのが必要な状況があります (例えば Bcc の時)。そうした状況と受信者の一部で MDN 要求が必要な場合との組合せで Disposition-Notification-To 頭が含まれるものと含まれないものも入れて3種類以上のメッセージが必要となるかもしれません。

Messages posted to newsgroups SHOULD NOT have a Disposition-Notification-To header.

ニュース組に投函するメッセージは Disposition-Notification-To 頭を持つべきではありません。

2.2. The Disposition-Notification-Options Header

Future extensions to this specification may require that information be supplied to the recipient's MUA for additional control over how and what MDNs are generated. The Disposition-Notification-Options header provides an extensible mechanism for such information. The syntax of this header, using the ABNF of RFC 822 [2], is as follows:

• Disposition-Notification-Options = "Disposition-Notification-Options" ":" disposition-notification-parameters

• disposition-notification-parameters = parameter *(";" parameter)

• parameter = attribute "=" importance "," 1#value value *("," value)

• importance = "required" / "optional"

An importance of "required" indicates that interpretation of the parameter is necessary for proper generation of an MDN in response to this request. If an MUA does not understand the meaning of the parameter, it MUST NOT generate an MDN with any disposition type other than "failed" in response to the request. An importance of "optional" indicates that an MUA that does not understand the meaning of this parameter MAY generate an MDN in response anyway, ignoring the value of the parameter.

重要度 required はこの要求に対する MDN の適切な生成のためにその引数の解釈が必要であることを示します。 MUA がその引数を理解できない場合には、この要求に対して failed 以外の配置型の MDN 応答を生成してはなりません。 重要度 optional はその引数を理解できない MUA もその引数の値を無視して MDN 応答を生成して構わないことを表します。

No parameters are defined in this specification. Parameters may be defined in the future by later revisions or extensions to this specification. Parameter attribute names beginning with "X-" will never be defined as standard names; such names are reserved for experimental use. MDN parameter names not beginning with "X-" MUST be registered with the Internet Assigned Numbers Authority (IANA) and described in a standards-track RFC or an experimental RFC approved by the IESG. (See Section 10 for a registration form.)

この仕様では引数を定義しません。引数はこの仕様の将来の改訂や拡張で定義するかもしれません。 X- で始まる引数属性名は標準の名前としては決して定義せず、 実験用に予約します。 X- で始まらない MDN 引数名は IANA に登録すると共に IESG で承認された標準化過程 RFC か実験的 RFC で説明しなければなりません。

If a required parameter is not understood or contains some sort of error, the receiving MUA SHOULD issue an MDN with a disposition type of "failed" (see Section 3.2.6), and include a Failure field (see Section 3.2.7) that further describes the problem. MDNs with the a disposition type of "failed" and a "Failure" field MAY also be generated when other types of errors are detected in the parameters of the Disposition-Notification-Options header.

必須の引数が理解できなかったか何らかの誤りを含む場合、 failed 配置型で問題を説明した Failure 欄を含んだ MDN を受信した MUA は発行するべきです。 配置型が failed で Failure な MDN は Disposition-Notification-Options 頭の引数で他の種類の誤りが検出された時にも生成して構いません。

However, an MDN with a disposition type of "failed" MUST NOT be generated if the user has indicated a preferance preference that MDNs are not to be sent. If user consent would be required for an MDN of some other disposition type to be sent, user consent SHOULD also be obtained before sending an MDN with a disposition type of "failed".

しかし、配置型 failed の MDN は利用者が MDN を送信しないと設定している時には生成してはなりません。 何か他の配置型の MDN を送るために利用者の同意が必要なら、 利用者の同意も配置型 failed の MDN を送信する前に得るべきです。

2.3. The Original-Recipient Header

Since electronic mail addresses may be rewritten while the message is in transit, it is useful for the original recipient address to be made available by the delivering MTA. The delivering MTA may be able to obtain this information from the ORCPT parameter of the SMTP RCPT TO command, as defined in RFC 1891 [8] [RFC-SMTP] and [RFC-DSN-SMTP].

電子メイル番地はメッセージの転送中に書き換えられるかもしれませんから、 配達する MTA が元の受信者の番地を利用可能にすると便利です。 配達 MTA はこの情報を SMTP RCPT TO 命令 の ORCPT 引数から得ることができるかもしれません。

[RFC-DSN-SMTP] is amended as follows: If this the ORCPT information is available, the delivering MTA SHOULD insert an Original-Recipient header at the beginning of the message (along with the Return-Path header). The delivering MTA MAY delete any other Original-Recipient headers that occur in the message. The syntax of this header, using the ABNF of RFC 822 [2], is as follows]]:

この ORCPT 情報が利用可能名場合、配達 MTA はメッセージのはじめに (Return-Path 頭と一緒に) Original-Recipient 頭を挿入するべきです。配達 MTA はメッセージにある他の Original-Recipient 頭を削除して構いません。 この頭の構文は次の通りです。

• original-recipient-header = "Original-Recipient" ":" address-type ";" generic-address

The address-type and generic-address token are as as specified in the description of the Original-Recipient field in section 3.2.3.

Original-Recipient 欄の字句 address-type と generic-address は3.2.3節にあります。

The purpose of carrying the original recipient information and returning it in the MDN is to permit automatic correlation of MDNs with the original message on a per-recipient basis.

元の受信者の情報を伝達してとそれを MDN で返すのは、 MDN を元のメッセージと受信者毎に自動的に関係づけるためです。

2.4. Use with the Message/Partial Content Type

The use of the headers Disposition-Notification-To, Disposition- Notification-Options, and Original-Recipient with the MIME

definition.

MIME message/partial 内容型と Disposition-Notification-To, Disposition-Notification-Options, Original-Recipient を併用するためには更に定義が必要です。

When a message is segmented into two or more message/partial fragments, the three headers mentioned in the above paragraph SHOULD be placed in the "inner" or "enclosed" message (using the terms of RFC 2046 [5] [RFC-MIME-MEDIA] ). These headers SHOULD NOT be used in the headers of any of the fragments themselves.

メッセージが2つ以上の message/partial 素片に分割される時は、前段落の3つの頭を (RFC 2046 の用語で言う) 内側の (囲まれた) メッセージに入れるべきです。これらの頭は素片自体の頭に使うべきではありません。

When the multiple message/partial fragments are reassembled, the following applies. If these headers occur along with the other headers of a message/partial fragment message, they pertain to an MDN to that will be generated for the fragment. If these headers occur in the headers of the "inner" or "enclosed" message (using the terms of RFC 2046 [5] [RFC-MIME-MEDIA] ), they pertain to an MDN to be generated for the reassembled message. Section 5.2.2.1 of RFC 2046 [5] [RFC-MIME-MEDIA] ) is amended to specify that, in addition to the headers specified there, the three headers described in this specification are to be appended, in order, to the headers of the reassembled message. Any occurrences of the three headers defined here in the headers of the initial enclosing message must not be copied to the reassembled message.

複数の message/partial 素片を再結合する時は次の通りとします。 これらの頭が message/partial 素片メッセージの他の頭と一緒に出現したなら、その素片について MDN を生成することになります。頭が (RFC 2045 の用語で言う) 内側の (囲まれた) メッセージの頭として出現するなら、 再結合したメッセージについて MDN を生成することを表します。 RFC 2046 の5.2.2.1節は、既に規定されている頭に加えてこの仕様で説明した 3つの頭も再結合メッセージの頭としてこの順で付加するよう改訂します。 ここで定義した3つの頭が最初の囲んでいるメッセージの頭に存在する時は再結合メッセージに複写してはなりません。

3. Format of a Message Disposition Notification

A message disposition notification is a MIME message with a top-level content-type of multipart/report (defined in RFC 1892 [7] [RFC-REPORT] ). When a multipart/report content is used to transmit an MDN:

メッセージ配置通知は最上位内容型が multipart/report の MIME メッセージです。 multipart/report 内容が MDN を転送するのに使われる時は、

• (a) The report-type parameter of the multipart/report content is "disposition-notification".
• (b) The first component of the multipart/report contains a human-readable explanation of the MDN, as described in RFC 1892 [7] [RFC-REPORT] ).
• (c) The second component of the multipart/report is of content-type message/disposition-notification, described in section 3.1 of this document.
• (d) If the original message or a portion of the message is to be returned to the sender, it appears as the third component of the multipart/report. The decision of whether or not to return the message or part of the message is up to the MUA generating the MDN. However, in the case of encrypted messages requesting MDNs, encrypted message text MUST be returned, if it is returned at all, only in its original encrypted form.

• multipart/report 内容の report-type 引数は disposition-notification です。
• multipart/report の最初の部分は MDN の人間可読な説明を含みます。
• multipart/report の2番目の部分はこの文書の 3.1節で説明する内容型 message/disposition-notification のものです。
• 元のメッセージの一部または全部を送信者に返す時は multipart/report の3番目の部分とします。 メッセージの一部または全部を返すかどうかの決定は MDN を生成する MUA が行います。しかし、暗号化メッセージが MDN を要求している場合、暗号化メッセージ文を全部返すのであれば元の暗号化形でのみ返さなければなりません。

NOTE: For message disposition notifications gatewayed from foreign systems, the headers of the original message may not be available. In this case, the third component of the MDN may be omitted, or it may contain "simulated" RFC 822 [RFC-MSGFMT] headers that contain equivalent information. In particular, it is very desirable to preserve the subject and date fields from the original message.

注意: 外部システムから関門を通じてやってくるメッセージ配置通知では元のメッセージの頭が利用できないかもしれません。 その場合、 MDN の3番目の部分は省略しても構いませんし、 等価な情報を含む仮想の RFC 2822 頭を含めても構いません。 特に主題欄や日付欄を元のメッセージから保存することが非常に望ましいと思われます。

The MDN MUST be addressed (in both the message header and the transport envelope) to the address(es) from the Disposition-Notification-To header from the original message for which the MDN is being generated.

MDN は MDN が生成される対象である元のメッセージの Disposition-Notification-To 頭の (単数または複数の) 番地に (メッセージの頭においても輸送封筒においても) 宛てなければなりません。

The From field of the message header of the MDN MUST contain the address of the person for whom the message disposition notification is being issued.

MDN のメッセージ頭の From 欄はメッセージ配置通知を発行する人の番地を含まなければなりません。

The envelope sender address (i.e., SMTP MAIL FROM) of the MDN MUST be null (<>), specifying that no Delivery Status Notification messages or other messages indicating successful or unsuccessful delivery are to be sent in response to an MDN.

MDN の送信者番地 (すなわち SMTP MAIL FROM) は空 (<>) にして配送状態通知メッセージやその他の配送の成功・ 不成功を知らせるメッセージが MDN に対する応答として送られないように指定しなければなりません。

A message disposition notification MUST NOT itself request an MDN. That is, it MUST NOT contain a Disposition-Notification-To header.

メッセージ配置通知自体は MDN を要求してはなりません。 つまり、 MDN は Disposition-Notification-To 頭を含んではなりません。

The Message-ID header (if present) for an MDN MUST be different from the Message-ID of the message for which the MDN is being issued.

MDN の Message-ID 頭は (あれば) MDN を発行する対象のメッセージの Message-ID とは異ならなければなりません。

A particular MDN describes the disposition of exactly one message for exactly one recipient. Multiple MDNs may be generated as a result of one message submission, one per recipient. However, due to the circumstances described in Section 2.1, MDNs may not be generated for some recipients for which MDNs were requested.

特定の MDN は丁度一人の受信者の丁度一つのメッセージの配置を説明します。 一つのメッセージ提出の結果として受信者毎に一つずつであわせて複数の MDN が生成されるかもしれません。しかし、2.1節で説明した状況により MDN が要求された受信者について MDN が生成されないこともあります。

3.1. The message/disposition-notification content-type

The message/disposition-notification content-type is defined as follows:

message/disposition-notification 内容型は次の通り定義します。

MIME type name

message

MIME subtype name

disposition-notification

Optional parameters

none

Encoding considerations

"7bit" encoding is sufficient and MUST be used to maintain readability when viewed by non-MIME mail readers.

Security considerations

discussed in section 6 of this memo.

MIME 型名

message

MIME 亜型名

disposition-notification

省略可能引数

なし

符号化

7bit で十分であり、非 MIME メイル読み器での表示時の可読性を維持するためにこれを使用しなければなりません。

安全性

このメモの6章で議論します。

The message/disposition-notification report type for use in the multipart/report is "disposition-notification".

multipart/report で使用する message/disposition-notification 報告型は disposition-notification です。

The body of a message/disposition-notification consists of one or more "fields" formatted according to the ABNF of RFC 822 [RFC-MSGFMT] header "fields" (see [2]). Using the ABNF of RFC 822, the The syntax of the message/disposition-notification content is as follows:

message/disposition-notification の本体は RFC 2822 の頭欄の ABNF に従って書式付けした1つ以上の欄から成ります。 message/disposition-notification 内容の構文は次の通りです。

      disposition-notification-content = [ reporting-ua-field CRLF ]
           [ mdn-gateway-field CRLF ]
           [ original-recipient-field CRLF ]
           final-recipient-field CRLF
           [ original-message-id-field CRLF ]
           disposition-field CRLF
           *( failure-field CRLF )
           *( error-field CRLF )
           *( warning-field CRLF )
           *( extension-field CRLF )

3.1.1. General conventions for fields

Since these fields are defined according to the rules of RFC 822 [2] [RFC-MSGFMT] , the same conventions for continuation lines and comments apply. Notification fields may be continued onto multiple lines by beginning each additional line with a SPACE or HTAB. Text which that appears in parentheses is considered a comment and not part of the contents of that notification field. Field names are case-insensitive, so the names of notification fields may be spelled in any combination of upper and lower case letters. Comments in notification fields may use the "encoded-word" construct defined in RFC 2047 [6] [RFC-MIME-HEADER] .

欄は RFC 2822 の規則に従って定義しますから、 継続行や注釈についても同じ規則を適用します。 通知欄は SPACE や HTAB で始まる追加行を使って複数行に継続できます。 括弧内に表れる文章は注釈とし、 その通知欄の内容の一部とはしません。欄名は大文字・ 小文字を区別しないので、大文字と小文字の任意の組合せで綴ることができます。 通知欄の注釈は RFC 2047 で定義される encoded-word 構造を使って構いません。

3.1.2. "*-type" subfields

Several fields consist of a "-type" subfield, followed by a semi-colon, followed by "*text". For these fields, the keyword used in the address-type or MTA-type subfield indicates the expected format of the address or MTA-name that follows.

幾つかの欄は -type 部分欄とセミコロンと *text から成ります。そのような欄では address-type 部分欄または MTA-type 部分欄で使う鍵語がその後の番地や MTA 名で期待される書式を示します。

The "-type" subfields are defined as follows:

-type 部分欄は次のように定義します。

(a) An "address-type" specifies the format of a mailbox address. For example, Internet Mail addresses use the "rfc822" address-type.

address-type はメイル箱番地の書式を指定します。 例えばインターネット・メイル番地は rfc822 address-type を使います。

address-type = atom

(b) An "MTA-name-type" specifies the format of a mail transfer agent name. For example, for an SMTP server on an Internet host, the MTA name is the domain name of that host, and the "dns" MTA-name-type is used.

MTA-name-type はメイル転送エージェント名の書式を指定します。 例えばインターネットのホストの SMTP]] 鯖では MTA 名はそのホストのドメイン名で、 dns MTA-name-type を使います。

mta-name-type = atom

Values for address-type and mta-name-type are case-insensitive. Thus, address-type values of "RFC822" and "rfc822" are equivalent.

address-type と mta-name-type の値は大文字・小文字を区別しません。ですから、 address-type 値 RFC822 と rfc822 は等価です。

The Internet Assigned Numbers Authority (IANA) will maintains a registry of address-type and mta-name-type values, along with descriptions of the meanings of each, or a reference to a one or more specifications that provide such descriptions. (The "rfc822" address-type is defined in RFC 1891 [8] [RFC-DSN-SMTP] .) Registration forms for address-type and mta-name-type appear in RFC 1894 [9] [RFC-DSN-FORMAT] .

IANA は address-type 値と mta-name-type 値とそれぞれの意味の説明またはその説明を提供する 1つ以上の仕様書への参照を添えた登録簿を管理します。 (rfc822 address-type は RFC 1891 で定義されています。) address-type と mta-name-type の登録フォームは RFC 1894 にあります。

IANA will not accept registrations for any address-type name that begins with "X-". These type names are reserved for experimental use.

IANA は X- で始まる address-type 名の登録を受け付けません。この型名は実験用に予約します。

3.1.3 Lexical tokens imported from RFC 822

The following lexical tokens, defined in RFC 822 [2], are used in the ABNF grammar for MDNs: atom, CRLF, mailbox, msg-id, text.

RFC 822 で定義されている字句 atom, CRLF, mailbox, msg-id, text を MDN の ABNF 文法で使います。

3.2. Message/disposition-notification Fields

3.2.1. The Reporting-UA field

• reporting-ua-field = "Reporting-UA" ":" ua-name [ ";" ua-product ]

• ua-name = *text

• ua-product = *text

The Reporting-UA field is defined as follows:

Reporting-UA 欄は次のように定義します。

An MDN describes the disposition of a message after it has been delivered to a recipient. In all cases, the Reporting-UA is the MUA that performed the disposition described in the MDN. This field is optional, but recommended. For Internet Mail user agents, it is recommended that this field contain both: the DNS name of the particular instance of the MUA that generated the MDN, and the name of the product. For example,

MDN はメッセージが受信者に配送された後にその配置を説明します。 すべての場合において Reporting-UA は MDN に説明されている配置を行った MUA とします。この欄は省略可能ですが、 記述することを推奨します。インターネット・メイル利用者エージェントでは、 この欄に MDN を生成した MUA の特定の実現値の DNS 名とその製品名の両方を含めることを推奨します。

• Reporting-UA: rogers-mac.dcrt.nih.gov; Foomail 97.1
• Reporting-UA: pc.example.com; Foomail 97.1

If the reporting MUA consists of more than one component (e.g., a base program and plug-ins), this may be indicated by including a list of product names.

報告する MUA が複数の部品 (例えば基底プログラムとプラグイン) で構成されている時は、製品名の並びを含めることによりこれを示して構いません。

3.2.2. The MDN-Gateway field

The MDN-Gateway field indicates the name of the gateway or MTA that translated a foreign (non-Internet) message disposition notification into this MDN. This field MUST appear in any MDN which that was translated by a gateway from a foreign system into MDN format, and MUST NOT appear otherwise.

MDN-Gateway 欄は外部 (非インターネット) メッセージ配置通知からこの MDN へ翻訳した関門または MTA の名前を示します。この欄は外部システムから MDN の書式に翻訳された MDN には必ず出現しなければなりません。また、 その他の MDN には出現してはなりません。

• mdn-gateway-field = "MDN-Gateway" ":" mta-name-type ";" mta-name

• mta-name = *text

For gateways into Internet Mail, the MTA-name-type will normally be "smtp", and the mta-name will be the Internet domain name of the gateway.

インターネット・メイルへの関門では MTA-name-type は通常 smtp であり、 mta-name は関門のインターネット・ドメイン名です。

3.2.3. Original-Recipient field

The Original-Recipient field indicates the original recipient address as specified by the sender of the message for which the MDN is being issued. For Internet Mail messages, the value of the Original-Recipient field is obtained from the Original-Recipient header from the message for which the MDN is being generated. If there is no Original-Recipient header in the message, then the Original-Recipient field MUST be omitted, unless the same information is reliably available some other way. If there is an Original-Recipient header in the original message (or original recipient information is reliably available some other way), then the Original-Recipient field must be supplied. If there is more than one Original-Recipient header in the message, the MUA may choose the one to use, or act as if no Original-Recipient header is present.

Original-Recipient 欄は MDN が発行された対象のメッセージの送信者が指定した元の受信者の番地を示します。 インターネット・メイルのメッセージでは、 Original-Recipient 欄の値は MDN が生成される対象のメッセージの Original-Recipient 頭から得ます。そのメッセージに Original-Recipient 頭がなければ、同じ情報が他の信頼できる方法で得られる場合を除き、 Original-Recipient 欄は省略しなければなりません。 元のメッセージに Original-Recipient 頭があれば (または何か別の信頼できる方法で元の受信者の情報が得られれば)、 Original-Recipient 欄を供給しなければなりません。 元のメッセージに複数 Original-Recipient 頭があれば、 MUA は一つ選んで使っても構いませんし、 Original-Recipient 頭が存在しないように動作しても構いません。

• original-recipient-field = "Original-Recipient" ":" address-type ";" generic-address

• generic-address = *text

The address-type field indicates the type of the original recipient address. If the message originated within the Internet, the address-type field field will normally be "rfc822", and the address will be according to the syntax specified in RFC 822 [2] [RFC-MSGFMT] . The value "unknown" should be used if the Reporting MUA cannot determine the type of the original recipient address from the message envelope.

address-type 欄は元の受信者の番地の型を示します。 メッセージがインターネット内で作成されたものなら、 address-type 欄は通常 rfc822 となり、番地は RFC 2822 で規定された構文に従います。報告する MUA が元の受信者の番地の型をメッセージの封筒から決定できなければ、 値 unknown を使うべきです。

This address is the same as that provided by the sender and can be used to automatically correlate MDN reports with original messages on a per recipient basis.

この番地は送信者が提供したものと同じであり、 MDN の報告と元のメッセージを受信者毎に自動的に関係付けるために使うことができます。

3.2.4. Final-Recipient field

The Final-Recipient field indicates the recipient for which the MDN is being issued. This field MUST be present.

Final-Recipient 欄は MDN を発行する対象の受信者を示します。この欄は存在しなければなりません。

The syntax of the field is as follows:

この欄の構文は次の通りです。

final-recipient-field = "Final-Recipient" ":" address-type ";" generic-address

The generic-address subfield of the Final-Recipient field MUST contain the mailbox address of the recipient (from the From header of the MDN) as it was when the MDN was generated by the MUA.

Final-Recipient 欄の generic-address 部分欄は MUA が MDN を生成した時の受信者のメイル箱の番地を (MDN の From 欄から) 含めなければなりません。

The Final-Recipient address may differ from the address originally provided by the sender, because it may have been transformed during forwarding and gatewaying into an totally unrecognizable mess. However, in the absence of the optional Original-Recipient field, the Final-Recipient field and any returned content may be the only information available with which to correlate the MDN with a particular message recipient.

メッセージはまったく認識できないところを転送されたり関門を通過したりして転送されてきたかもしれませんから、 Final-Recipient 番地は元々送信者が指定した番地とは違っているかもしれません。 しかし、省略可能な Original-Recipient 欄が存在しない時には Final-Recipient 欄と返される内容だけが MDN と特定のメッセージ受信者を関係付けるために使える情報となります。

The address-type subfield indicates the type of address expected by the reporting MTA in that context. Recipient addresses obtained via SMTP will normally be of address-type "rfc822".

address-type 部分欄は報告する MTA がその文脈で期待する番地の型を示します。 SMTP で得られる受信者の番地の address-type は通常 rfc822 です。

Since mailbox addresses (including those used in the Internet) may be case sensitive, the case of alphabetic characters in the address MUST be preserved.

メイル箱番地は (インターネットで使われているものも含めて) 大文字・小文字を区別を行うので、番地の大文字・ 小文字は保存しなければなりません。

3.2.5. Original-Message-ID field

The Original-Message-ID field indicates the message-ID of the message for which the MDN is being issued. It is obtained from the Message-ID header of the message for which the MDN is issued. This field MUST be present if the original message contained a Message-ID header. The syntax of the field is as follows:

Original-Message-ID 欄は MDN が発行される対象のメッセージのメッセージ識別子を示します。 メッセージ識別子は MDN が発行される対象のメッセージの Message-ID 頭から得ます。この欄は元のメッセージが Message-ID を含む時には存在しなければなりません。 この欄の構文は次の通りです。

• original-message-id-field = "Original-Message-ID" ":" msg-id

The msg-id token is as specified in RFC 822 [2] [RFC-MSGFMT] .

字句 msg-id は RFC 2822 で定義されています。

3.2.6. Disposition field

The Disposition field indicates the action performed by the Reporting-MUA on behalf of the user. This field MUST be present.

Disposition 欄は Reporting-MUA が利用者に代わって行った動作を示します。 この欄は存在しなければなりません。

The syntax for the Disposition field is:

Disposition 欄の構文は次の通りです。

•     disposition-field =
                "Disposition" ":" disposition-mode ";"
                           disposition-type
                [ "/" disposition-modifier
                *( "," disposition-modifier ) ]

• disposition-mode = action-mode "/" sending-mode

• action-mode = "manual-action" / "automatic-action"

• sending-mode = "MDN-sent-manually" / "MDN-sent-automatically"

•       disposition-type = "displayed"
                        / "dispatched"
                        / "processed"
                         / "deleted"
                        / "denied"
                        / "failed"

•      disposition-modifier = ( "error" / "warning" )
                            / ( "superseded" / "expired" /
                                "mailbox-terminated" )
       disposition-modifier = "error"
                             / disposition-modifier-extension

• disposition-modifier-extension = atom

The disposition-mode, disposition-type, and disposition-modifier may be spelled in any combination of upper and lower case characters.

disposition-mode, disposition-type, disposition-modifier は大文字・ 小文字の任意の組合せで綴って構いません。

3.2.6.1. Disposition modes

The following disposition modes are defined:

次の配置モードを定義します。

"manual-action" The disposition described by the disposition type was a result of an explicit instruction by the user rather than some sort of automatically performed action.

manual-action

配置型で説明された配置は何らかの自動実行行為ではなく、 利用者の明示的な指示による結果です。

"automatic-action" The disposition described by the disposition type was a result of an automatic action, rather than an explicit instruction by the user for this message.

automatic-action

配置型で説明された配置はこのメッセージに対する利用者の明示的な指示による結果ではなく、 自動的な動作の結果です。

"Manual-action" and "automatic-action" are mutually exclusive. One or the other must MUST be specified.

manual-action と automatic-action は相互に排他的です。どちらか1つだけを指定しなければなりません。

"MDN-sent-manually" The user explicitly gave permission for this particular MDN to be sent.

MDN-sent-manually

利用者が明示的にこの MDN を送信することを許可しました。

"MDN-sent-automatically" The MDN was sent because the MUA had previously been configured to do so automatically.

MDN-sent-automatically

MDN は以前に MUA が自動的に送信するように設定されているので 送信しました。

"MDN-sent-manually" and "MDN-sent-automatically" are mutually exclusive. One or the other must MUST be specified.

MDN-sent-manually と MDN-sent-automatically は相互に排他的です。どちらか1つだけを指定しなければなりません。

3.2.6.2. Disposition types

The following disposition-types are defined:

次の disposition-type を定義します。

"displayed" The message has been displayed by the MUA to someone reading the recipient's mailbox. There is no guarantee that the content has been read or understood.

displayed

メッセージは MUA から受信者のメイル箱を読む誰かに表示されました。 内容が読まれ理解されたという保証はありません。

"dispatched" The message has been sent somewhere in some manner (e.g., printed, faxed, forwarded) without necessarily having been previously displayed to the user. The user may or may not see the message later.

dispatched

メッセージは必ずしも利用者に以前に表示されずに何らかの形でどこかに送信 (例えば印刷、FAX、転送) されました。 利用者は後からメッセージを見たかもしれませんし、 見ていないかもしれません。

"processed" The message has been processed in some manner (i.e., by some sort of rules or server) without being displayed to the user. The user may or may not see the message later, or there may not even be a human user associated with the mailbox.

processed

メッセージは利用者に表示されることなく何らかの形で (何らかの規則や鯖により) 処理されました。利用者は後からメッセージを見たかもしれませんし、 見ていないかもしれません。あるいはそのメイル箱に関連付けられた人間の利用者は存在すらしていないかもしれません。

"deleted" The message has been deleted. The recipient may or may not have seen the message. The recipient might "undelete" the message at a later time and read the message.

delete

メッセージは削除されました。 受信者はメッセージを見たかもしれませんし、 見ていないかもしれません。受信者は後からメッセージの削除を取消して内容を読むかもしれません。

"denied" The recipient does not wish the sender to be informed of the message's disposition. A UA may also siliently ignore message disposition requests in this situation.

denied

受信者はメッセージの配置を送信者に通知したくないと思っています。 MUA はこの状況下では黙ってメッセージ配置通知要求を無視しても構いません。

"failed" A failure occurred that prevented the proper generation of an MDN. More information about the cause of the failure may be contained in a Failure field. The "failed" disposition type is not to be used for the situation in which there is is some problem in processing the message other than interpreting the request for an MDN. The "processed" or other disposition type with appropriate disposition modifiers is to be used in such situations.

failed

失敗があって MDN を適切に生成できませんでした。失敗の原因についての詳しい情報が Failure 欄に含まれているかもしれません。 failed 配置型は MDN の要求の解釈以外でメッセージの処理に問題が発生した場合に対しては使いません。 そのような状況においては processed などの配置型を適切な配置修飾子と一緒に使います。

3.2.6.3. Disposition modifiers

The following disposition modifiers are defined:

次の配置修飾子を定義します。

"error" An error of some sort occurred that prevented successful processing of the message. Further information is contained in an Error field.

error

メッセージの処理を正常に行えないような何らかの誤りが発生しました。 更なる情報が Error 欄に含まれています。

"warning" The message was successfully processed but some sort of exceptional condition occurred. Further information is contained in a Warning field.

warning

メッセージは正常に処理されましたが、 何らかの例外的状況が発生しました。更なる情報が Warning 欄に含まれています。

"superseded" The message has been automatically rendered obsolete by another message received. The recipient may still access and read the message later.

superseded

メッセージは他の受信したメッセージにより自動的に廃止とされました。 受信者はそれでも後からそのメッセージにアクセスして読むことができるかもしれません。

"expired" The message has reached its expiration date and has been automatically removed from the recipient's mailbox.

expired

メッセージは満期の日付に到達し、 受信者のメイル箱から自動的に削除されました。

"mailbox-terminated" The recipient's mailbox has been terminated and all message in it automatically removed.

mailbox-terminated

受信者のメイル箱は終了し、 すべてのメッセージが自動的に削除されました。

< "Obsoleted", "expired", and "terminated" are to be used with the "deleted" disposition type and the "autoaction" and "autosent" disposition modifiers.

obsoleted, expired, terminated は配置型 deleted および配置修飾子の autoaction や autosent と併用します。

Only the extension disposition modifiers is defined:

拡張配置修飾子だけを定義します。

disposition-modifier-extension Additional disposition Disposition modifiers may be defined in the future by later revisions or extensions to this specification. Disposition value names beginning with "X-" will never be defined as standard values; such names are reserved for experimental use. MDN disposition value names NOT beginning with "X-" MUST be registered with the Internet Assigned Numbers Authority (IANA) and described in a standards-track RFC or an experimental RFC approved by the IESG. (See Section 10 for a registration form.) MDNs with disposition modifier names not understood by the receiving MUA MAY be silently ignored or placed in the user's mailbox without special inter-pretation. They MUST not cause any error message to be sent to the sender of the MDN.

配置修飾子はこの仕様の将来の改訂版や拡張で定義されるかもしれません。 名前が X- で始まる配置値は標準の値として定義されることはなく、 実験用に予約します。 X- で始まらない MDN 配置値は IANA に登録すると共に IESG で承認された標準化過程 RFC または実験的 RFC で説明しなければなりません。受信した MUA が理解できない配置修飾子名を使った MDN は特別な解釈を行わずに無視したり利用者のメイル箱に入れたりして構いません。 しかし MDN の送信者に誤りメッセージを送信してはなりません。

If an MUA developer does not wish to register the meanings of such disposition modifier extensions, "X-" modifiers may be used for this purpose. To avoid name collisions, the name of the MUA implementation should follow the "X-", (e.g., "X-Foomail-fratzed").

MUA 開発者が配置修飾子拡張の意味を登録したくない時は、 X- 修飾子を使って構いません。名前の衝突を防ぐために MUA 実装の名前を X- の後に (例えば X-Foomail- のように) 付けるべきです。

It is not required that an MUA be able to generate all of the possible values of the Disposition field.

MUA が Disposition 欄の可能なすべての値を生成できる必要はありません。

One and only one MDN may be issued on behalf of each particular recipient by their user agent. A user agent MUST NOT issue more than one MDN on behalf of each particular recipient. That is, once an MDN has been issued on behalf of a recipient, no further MDNs may be issued on behalf of that recipient, even if another disposition is performed on the message. However, if a message is forwarded, a "dispatched" MDN may been issued for the recipient doing the forwarding and the recipient of the forwarded message may also cause an MDN to be generated.

利用者エージェントは受信者それぞれに対して複数の MDN]] を発行してはなりません。つまり、一度ある受信者に代わって MDN を発行したら、メッセージに他の配置を行ったとしても更に MDN を発行してはいけません。ただし、メッセージが転送される時は転送する受信者に代わって dispatched MDN を発行しても構いませんし、 転送メッセージの受信者も MDN を生成させて構いません。

3.2.7. Failure, Error, and Warning fields

The Failure, Error, and Warning fields are used to supply additional information in the form of text messages when the "failure" disposition type, "error" disposition modifier, and/or the "warning" disposition modifier appear. The syntax is as follows:

欄 Failure, Error, Wawrning は failure 配置型、 error 配置修飾子及び/又は warning 配置修飾子が出現する時に追加情報を文章で供給するために使います。 構文は次の通りです。

• failure-field = "Failure" ":" *text

• error-field = "Error" ":" *text

• warning-field = "Warning" ":" *text

3.3. Extension-fields

Additional MDN fields may be defined in the future by later revisions or extensions to this specification. Extension-field names beginning with "X-" will never be defined as standard fields; such names are reserved for experimental use. MDN field names NOT beginning with "X-" MUST be registered with the Internet Assigned Numbers Authority (IANA) and described in a standards-track RFC or an experimental RFC approved by the IESG. (See Section 10 for a registration form.)

この仕様の将来の改訂版や拡張は追加の MDN 欄を定義するかもしれません。 X- で始まる拡張欄名は標準の欄として定義することはなく、 実験用に予約します。 X- で始まらない MDN 欄名は IANA に登録すると共に IESG で承認された標準化過程 RFC または実験的 RFC で説明しなければなりません。

Extension MDN fields MDN Extension-fields may be defined for the following reasons:

MDN 拡張欄は次のような理由で定義されるかもしれません。

(a) To allow additional information from foreign disposition reports to be tunneled through Internet MDNs. The names of such MDN fields should begin with an indication of the foreign environment name (e.g., X400-Physical-Forwarding-Address).

外部配置報告からの情報をインターネット MDN を通じてトンネル化できるようにするため。この場合 MDN 欄の名前は外部環境名で始めるべきです (例: X400-Physical-Forwarding-Address)。

(b) To allow transmission of diagnostic information which that is specific to a particular mail user agent (MUA). The names of such MDN fields should begin with an indication of the MUA implementation which that produced the MDN. (e.g. Foomail-information).

特定の MUA 実装特有の診断情報の転送ができるようにするため。 この場合 MDN 欄の名前は MUA 実装の名前で始めるべきです (例: Foomail-information)。

訳注: このような目的の欄が IESG の評価を通過できるとは到底思えませんが...

If an application developer does not wish to register the meanings of such extension fields, "X-" fields may be used for this purpose. To avoid name collisions, the name of the application implementation should follow the "X-", (e.g., "X-Foomail-Log-ID" or "X-Foomail-EDI-info").

応用開発者がこのような拡張欄の意味を登録したくない時は、 X- 欄を使って構いません。名前の衝突を防ぐため、 応用実装の名前を X- の後に付けるべきです (例えば X-Foomail-Log-ID や X-Foomail-EDI-Info)。

4. Timeline of events

The following timeline shows when various events in the processing of a message and generation of MDNs take place:

次の時間表はメッセージの処理と MDN の生成において色々な事象が起こる時期を示しています。

-- User composes message

-- User tells MUA to send message

-- MUA passes message to MTA (original recipient information passed along)

-- MTA sends message to next MTA

-- Final MTA receives message

-- Final MTA delivers message to MUA (possibly generating a DSN)

-- MUA performs automatic processing and generates corresponding MDNs ("dispatched", "processed", "deleted", "denied", or "failed" disposition type with "automatic-action" and "MDN-sent-automatically" disposition modes)

-- MUA displays list of messages to user

-- User selects a message and requests that some action be performed on it.

-- MUA performs requested action and, with user's permission, sends an appropriate MDN ("displayed", "dispatched", "processed", "deleted", "denied", or "failed" disposition type, with "manual-action" and "MDN-sent-manually" or "MDN-sent-automatically" disposition mode).

-- User possibly performs other actions on message, but no further MDNs are generated.

1. 利用者がメッセージを作成
2. 利用者が MUA にメッセージを送信するよう指示
3. MUA がメッセージを MTA に渡す (元の受信者の情報が一緒に渡される)
4. MTA が次の MTA にメッセージを送信
5. 最後の [{MTA]] がメッセージを受信
6. 最後の MTA が MUA にメッセージを配送 (DSN を生成する場合も)
7. MUA が自動処理を実行して対応する MDN を生成 (配置型は dispatched, processed, deleted, denied, failed で、 配置モードは automatic-action と MDN-sent-automatically)
8. MUA がメッセージの一覧を利用者に表示
9. 利用者がメッセージを選択して、 それに対して何らかの動作を実行
10. MUA が要求された動作を実行して適切な MDN を生成 (配置型は displayed, dispatched, processed, deleted, denied, failed で、 配置モードは manual-action と MDN-sent-manually または MDN-sent-automatically)
11. 利用者がそのメッセージに対して更に他の動作を実行するかもしれないが、 もう MDN は生成しない

5. Conformance and Usage Requirements

An MUA or gateway conforms to this specification if it generates MDNs according to the protocol defined in this memo. It is not necessary to be able to generate all of the possible values of the Disposition field.

MUA や関門は、このメモで定義したプロトコルに従って MDN を生成する時、この仕様に適合します。 Disposition 欄が取り得る全ての値を生成できる必要はありません。

MUAs and gateways MUST NOT generate the Original-Recipient field of an MDN unless the mail protocols provide the address originally specified by the sender at the time of submission. Ordinary SMTP does not make that guarantee, but the SMTP extension defined in RFC 1891 [8] [RFC-DSN-SMTP] permits such information to be carried in the envelope if it is available. The Original-Recipient header defined in this document provides a way for the MTA to pass the original recipient address to the MUA.

MUA と関門は送信者が提出時に元々指定した番地をメイル・プロトコルが提供していない限り MDN の Original-Recipient 欄を生成してはなりません。 普通 SMTP はこれを保証しませんが、 RFC 1891 で定義された SMTP の拡張を使えばこの情報が利用可能な時封筒で伝達できます。 この文書で定義された Original-Recipient 頭は MTA が元の受信者の番地を MUA に渡す手段を提供しています。

Each sender-specified recipient address may result in more than one MDN. If an MDN is requested for a recipient that is forwarded to multiple recipients of an "alias" (as defined in RFC 1891 [8] [RFC-DSN-SMTP] , section 6.2.7.3), each of the recipients may issue an MDN.

送信者が指定した受信者の番地それぞれについて複数の MDN が発行されることがあります。ある受信者に MDN が要求され、それが別名の複数の受信者に転送されると、 受信者のそれぞれが MDN を発行するかもしれません。

Successful distribution of a message to a mailing list exploder SHOULD be considered the final disposition of the message. A mailing list exploder may MAY issue an MDN with a disposition type of "processed" and disposition modes of "automatic-action" and "MDN-sent-automatically" indicating that the message has been forwarded to the list. In this case, the request for MDNs is not propogated propagated to the members of the list.

メイリング・リスト配送器へメッセージの配布が成功したら、 それをもってメッセージの最終的な配置とみなすべきです。 メイリング・リスト配送器は配送型が processed では移送モードが automatic-action と MDN-sent-automatically であってメッセージがメイリング・リストに転送されたことを示す MDN を発行して構いません。この場合、 MDN の要求はメイリング・リストの参加者には伝播しません。

Alternatively, the mailing list exploder may MAY issue no MDN and propogate propagate the request for MDNs to all members of the list. The latter behavior is not recommended for any but small, closely knit lists, as it might cause large numbers of MDNs to be generated and may cause confidential subscribers to the list to be revealed. It is also permissible for the mailing list exploder to The mailing list exploder MAY also direct MDNs to itself, correlate them, and produce a report to the original sender of the message.

代わりにメイリング・リスト配送器は MDN を発行せずに MDN の要求をメイリング・リストの参加者に伝播しても構いません。 後者の動作は大量の MDN が生成されてしまいますし、 メイリング・リストの参加者が分かってしまいますから、 小さな親しい参加者のメイリング・リスト以外では推奨しません。 メイリング・リスト配送器は MDN を自身に向けて送らせて、元のメッセージの送信者への報告を作成しても構いません。

This specification places no restrictions on the processing of MDNs received by user agents or mailing lists.

この仕様は利用者エージェントやメイリング・リストが受信した MDN の処理については何の制限も行いません。

6. Security Considerations

The following security considerations apply when using MDNs:

MDN を使う時は次の安全上の考慮が必要です。

6.1. Forgery

MDNs may be forged as easily as ordinary Internet electronic mail. User agents and automatic mail handling facilities (such as mail distribution list exploders) that wish to make automatic use of MDNs should take appropriate precautions to minimize the potential damage from denial-of-service attacks.

Security threats related to forged MDNs include the sending of:

 
    (a)  A falsified disposition notification when the indicated
-        disposition of the message has not actually ocurred,
+        disposition of the message has not actually occurred,
 
    (b)  Unsolicited MDNs
 
-6.2 Confidentiality

• Another dimension of security is confidentiality. There may be cases + Another dimension of security is privacy. There may be cases in which a message recipient does not wish the disposition of
• messages addressed to him to be known or is concerned that the + messages addressed to him to be known, or is concerned that the sending of
• sending of MDNs may reveal other confidential information (e.g., when
• the message was read). In this situation, it is acceptable for the
• UA to issue "denied" MDNs or to silently ignore requests for MDNs. + MDNs may reveal other sensitive information (e.g., when the message + was read). In this situation, it is acceptable for the MUA to issue + "denied" MDNs or to silently ignore requests for MDNs.

   
      If the Disposition-Notification-To header is passed on unmodified
      when a message is distributed to the subscribers of a mailing list,
      the subscribers to the list may be revealed to the sender of the
      original message by the generation of MDNs.
   
      Headers of the original message returned in part 3 of the
      multipart/report could reveal confidential information about host
      names and/or network topology inside a firewall.
   
      An unencrypted MDN could reveal confidential information about an
      encrypted message, especially if all or part of the original message
      is returned in part 3 of the multipart/report.  Encrypted MDNs are
      not defined in this specification.
   
  -   In general, any optional MDN field may be omitted if the Reporting UA
  -   site or user determines that inclusion of the field would impose too
  -   great a compromise of site confidentiality.  The need for such
  +   In general, any optional MDN field may be omitted if the Reporting
  +   MUA site or user determines that inclusion of the field would impose
  +   too great a compromise of site confidentiality.  The need for such
      confidentiality must be balanced against the utility of the omitted
      information in MDNs.
   
  -6.3 Non-Repudiation
   
  -   Within the framework of today's Internet Mail, the MDNs defined in
  -   this document provide valuable information to the mail user; however,
  -   MDNs can not be relied upon as a guarantee that a message was or was
  -   not not seen by the recipient.  Even if MDNs are not actively forged,
  -   they may be lost in transit.  The MDN issuing mechanism may be
  -   bypassed in some manner by the recipient.
  +   In some cases, someone with access to the message stream may use the
  +   MDN request mechanism to monitor the mail reading habits of a target.
  +   If the target is known to generate MDN reports, they could add a
  +   disposition-notification-to field containing the envelope from
  +   address along with a source route.  The source route is ignored in
  +   the comparison so the addresses will always match.  But if the source
  +   route is honored when the notification is sent, it could direct the
  +   message to some other destination.  This risk can be minimized by not
  +   sending MDN's automatically.
  +
  +6.3.  Non-Repudiation
  +
  +   MDNs do not provide non-repudiation with proof of delivery.  Within
  +   the framework of today's Internet Mail, the MDNs defined in this
  +   document provide valuable information to the mail user; however, MDNs
  +   cannot be relied upon as a guarantee that a message was or was not
  +   seen by the recipient.  Even if MDNs are not actively forged, they
  +   may be lost in transit.  The recipient may bypass the MDN issuing
  +   mechanism in some manner.
  +
  +   One possible solution for this purpose can be found in RFC 2634
  +   [SEC-SERVICES].
  +
  +6.4.  Mail Bombing
  +
  +   The MDN request mechanism introduces an additional way of mailbombing
  +   a mailbox.  The MDN request notification provides an address to which
  +   MDN's should be sent.  It is possible for an attacking agent to send
  +   a potentially large set of messages to otherwise unsuspecting third
  +   party recipients with a false "disposition-notification-to:" address.
  +   Automatic, or simplistic processing of such requests would result in
  +   a flood of MDN notifications to the target of the attack.  Such an
  +   attack could overrun the capacity of the targeted mailbox and deny
  +   service.
  +
  +   For that reason, MDN's SHOULD NOT be sent automatically where the
  +   "disposition-notification-to:" address is different from the envelope
  +   MAIL FROM address.  See section 2.1 for further discussion.
   
  * 7.  Collected Grammar
   
  -   NOTE:  The following lexical tokens are defined in RFC 822:  atom,
  -   CRLF, mailbox, msg-id, text.  The definitions of attribute and value
  -   are as in the definition of the Content-Type header in RFC 2045 [4].
  +   NOTE:  The following lexical tokens are defined in [RFC-MSGFMT]:
  +   atom, CRLF, mailbox, msg-id, text.  The definitions of attribute and
  +   value are as in the definition of the Content-Type header in [RFC-
  +   MIME-BODY].

Message headers:

 
-   mdn-request-header = "Disposition-Notification-To" ":" 1#mailbox
 
-   Disposition-Notification-Options =
-        "Disposition-Notification-Options" ":"
-        disposition-notification-parameters
 
-   disposition-notification-parameters = parameter *(";" parameter)
+  mdn-request-header =
+     "Disposition-Notification-To" ":"
+            mailbox *("," mailbox)
+
+  Disposition-Notification-Options =
+            "Disposition-Notification-Options" ":"
+            disposition-notification-parameters
+
+  disposition-notification-parameters =
+            parameter *(";" parameter)
 
-   parameter = attribute "=" importance "," 1#value
+  parameter = attribute "=" importance "," value *("," value)
 
    importance = "required" / "optional"
 
    original-recipient-header =
         "Original-Recipient" ":" address-type ";" generic-address

    Report content:
 
  disposition-notification-content =
            [ reporting-ua-field CRLF ]
        [ mdn-gateway-field CRLF ]
        [ original-recipient-field CRLF ]
        final-recipient-field CRLF
        [ original-message-id-field CRLF ]
        disposition-field CRLF
        *( failure-field CRLF )
        *( error-field CRLF )
        *( warning-field CRLF )
        *( extension-field CRLF )
 
    address-type = atom
 
    mta-name-type = atom

  reporting-ua-field = "Reporting-UA" ":" ua-name [ ";" ua-product ]

    ua-name = *text
 
    ua-product = *text
 
    mdn-gateway-field = "MDN-Gateway" ":" mta-name-type ";" mta-name
 
    mta-name = *text
 
-   original-recipient-field =
-        "Original-Recipient" ":" address-type ";" generic-address
+  original-recipient-field
+            = "Original-Recipient" ":" address-type ";"
+            generic-address

  generic-address = *text

  final-recipient-field =
            "Final-Recipient" ":" address-type ";" generic-address

• disposition-field = "Disposition" ":" disposition-mode ";"
• disposition-type
• [ '/' disposition-modifier
• *( "," dispostion-modifier ) ] + disposition-field = + "Disposition" ":" disposition-mode ";" + disposition-type + [ "/" disposition-modifier + *( "," disposition-modifier ) ]

   
      disposition-mode = action-mode "/" sending-mode
   
      action-mode = "manual-action" / "automatic-action"
   
      sending-mode = "MDN-sent-manually" / "MDN-sent-automatically"
   
      disposition-type = "displayed"
  -                    / "dispatched"
  -                    / "processed"
                       / "deleted"
  -                    / "denied"
  -                    / "failed"
   
  -   disposition-modifier = ( "error" / "warning" )
  -                        / ( "superseded" / "expired" /
  -                            "mailbox-terminated" )
  -                        / disposition-modifier-extension
  +  disposition-modifier =  "error" / disposition-modifier-extension
   
      disposition-modifier-extension = atom
   
      original-message-id-field = "Original-Message-ID" ":" msg-id
   
      failure-field = "Failure" ":" *text
   
      error-field = "Error" ":" *text
   
      warning-field = "Warning" ":" *text
   
      extension-field = extension-field-name ":" *text
   
      extension-field-name = atom
   
  * 8.  Guidelines for Gatewaying MDNs
   
      NOTE:  This section provides non-binding recommendations for the
      construction of mail gateways that wish to provide semi-transparent
      disposition notifications between the Internet and another electronic
      mail system.  Specific MDN gateway requirements for a particular pair
      of mail systems may be defined by other documents.
   
  -8.1 Gatewaying from other mail systems to MDNs
  +8.1.  Gatewaying from other mail systems to MDNs
   
  -   A mail gateway may issue an MDN to convey the contents of a "foreign"
  -   disposition notification over Internet Mail.  When there are
  -   appropriate mappings from the foreign notification elements to MDN
  +   A mail gateway may issue an MDN to convey the contents of a "foreign"
  +   disposition notification over Internet Mail.  When there are
  +   appropriate mappings from the foreign notification elements to MDN
      fields, the information may be transmitted in those MDN fields.
      Additional information (such as might be needed to tunnel the foreign
      notification through the Internet) may be defined in extension MDN
      fields.  (Such fields should be given names that identify the foreign
  -   mail protocol, e.g. X400-* for X.400 protocol elements)
  +   mail protocol, e.g., X400-* for X.400 protocol elements).
   
      The gateway must attempt to supply reasonable values for the
      Reporting-UA, Final-Recipient, and Disposition fields.  These will
      normally be obtained by translating the values from the foreign
      notification into their Internet-style equivalents.  However, some
      loss of information is to be expected.
   
  -   The sender-specified recipient address, and the original message-id,
  +   The sender-specified recipient address and the original message-id,
      if present in the foreign notification, should be preserved in the
      Original-Recipient and Original-Message-ID fields.
   
      The gateway should also attempt to preserve the "final" recipient
      address from the foreign system.  Whenever possible, foreign protocol
      elements should be encoded as meaningful printable ASCII strings.
   
      For MDNs produced from foreign disposition notifications, the name of
      the gateway MUST appear in the MDN-Gateway field of the MDN.
   
  -8.2 Gatewaying from MDNs to other mail systems
  +8.2.  Gatewaying from MDNs to other mail systems
   
      It may be possible to gateway MDNs from the Internet into a foreign
      mail system.  The primary purpose of such gatewaying is to convey
      disposition information in a form that is usable by the destination
      system.  A secondary purpose is to allow "tunneling" of MDNs through
  -   foreign mail systems, in case the MDN may be gatewayed back into the
  +   foreign mail systems in case the MDN may be gatewayed back into the
      Internet.
   
      In general, the recipient of the MDN (i.e., the sender of the
      original message) will want to know, for each recipient:  the closest
      available approximation to the original recipient address, and the
      disposition (displayed, printed, etc.).
   
      If possible, the gateway should attempt to preserve the Original-
  -   Recipient address and Original-Message-ID (if present), in the
  +   Recipient address and Original-Message-ID (if present) in the
      resulting foreign disposition report.
   
  -   If it is possible to tunnel an MDN through the destination
  -   environment, the gateway specification may define a means of
  -   preserving the MDN information in the disposition reports used by
  -   that environment.
  +   If it is possible to tunnel an MDN through the destination
  +   environment, the gateway specification may define a means of
  +   preserving the MDN information in the disposition reports used by
  +   that environment.
  +
  +8.3.  Gatewaying of MDN-requests to other mail systems
  +
  +   By use of the separate disposition-notification-to request header,
  +   this specification offers a richer functionality than most, if not
  +   all, other email systems.  In most other email systems, the
  +   notification recipient is identical to the message sender as
  +   indicated in the "from" address.  There are two interesting cases
  +   when gatewaying into such systems:
  +
  +   1) If the address in the disposition-notification-to header is
  +      identical to the address in the SMTP "MAIL FROM", the expected
  +      behavior will result, even if the disposition-notification-to
  +      information is lost.  Systems should propagate the MDN request.
  +
  +   2) If the address in the disposition-notification-to header is
  +      different from the address in the SMTP "MAIL FROM", gatewaying
  +      into a foreign system without a separate notification address will
  +      result in unintended behavior.  This is especially important when
  +      the message arrives via a mailing list expansion software that may
  +      specifically replace the SMTP "MAIL FROM" address with an
  +      alternate address.  In such cases, the MDN request should not be
  +      gatewayed and should be silently dropped.  This is consistent with
  +      other forms of non-support for MDN.
   
  * 9.  Example
   
      NOTE:  This example is provided as illustration only, and is not
      considered part of the MDN protocol specification.  If the example
      conflicts with the protocol definition above, the example is wrong.
   
      Likewise, the use of *-type subfield names or extension fields in
      this example is not to be construed as a definition for those type
      names or extension fields.
   
  -9.1 This is an MDN issued after a message has been displayed to the user
  +   This is an MDN issued after a message has been displayed to the user
      of an Internet Mail user agent.
   
      Date: Wed, 20 Sep 1995 00:19:00 (EDT) -0400
  -   From: Joe Recipient <Joe_Recipient@mega.edu>
  +   From: Joe Recipient <Joe_Recipient@example.com>
  -   Message-Id: <199509200019.12345@mega.edu>
  +   Message-Id: <199509200019.12345@example.com>
      Subject: Disposition notification
  -   To: Jane Sender <Jane_Sender@huge.com>
  +   To: Jane Sender <Jane_Sender@example.org>
      MIME-Version: 1.0
      Content-Type: multipart/report; report-type=disposition-notification;
  -         boundary="RAA14128.773615765/mega.edu"
  +      boundary="RAA14128.773615765/example.com"
   
  -   --RAA14128.773615765/mega.edu
  +   --RAA14128.773615765/example.com
   
      The message sent on 1995 Sep 19 at 13:30:00 (EDT) -0400 to Joe
  -   Recipient <Joe_Recipient@mega.edu> with subject "First draft of
  +   Recipient <Joe_Recipient@example.com> with subject "First draft of
      report" has been displayed.  This is no guarantee that the message
      has been read or understood.
   
  -   --RAA14128.773615765/mega.edu
  +   --RAA14128.773615765/example.com
      content-type: message/disposition-notification
   
  -   Reporting-UA: joes-pc.cs.mega.edu; Foomail 97.1
  -   Original-Recipient: rfc822;Joe_Recipient@mega.edu
  -   Final-Recipient: rfc822;Joe_Recipient@mega.edu
  -   Original-Message-ID: <199509192301.23456@huge.com>
  +   Reporting-UA: joes-pc.cs.example.com; Foomail 97.1
  +   Original-Recipient: rfc822;Joe_Recipient@example.com
  +   Final-Recipient: rfc822;Joe_Recipient@example.com
  +   Original-Message-ID: <199509192301.23456@example.org>
      Disposition: manual-action/MDN-sent-manually; displayed
   
  -   --RAA14128.773615765/mega.edu
  +   --RAA14128.773615765/example.com
      content-type: message/rfc822
   
  -   [original message goes here]
  +   [original message optionally goes here]
  -
  -   --RAA14128.773615765/mega.edu--
  +   --RAA14128.773615765/example.com--

+10. IANA Considerations

• 10. IANA Registration Forms

+ This document specifies three types of parameters that must be + registered with the Internet Assigned Numbers Authority (IANA).

 
    The forms below are for use when registering a new parameter name for
    the Disposition-Notification-Options header, a new disposition
    modifier name, or a new MDN extension field.  Each piece of
    information required by a registration form may be satisfied either
    by providing the information on the form itself, or by including a
    reference to a published, publicly available specification that
    includes the necessary information.  IANA MAY reject registrations
-   because of incomplete registration forms, imprecise specifications,
+   because of incomplete registration forms or incomplete
-   or inappropriate names.
+   specifications.
 
-   To register, complete the applicable form below and send it via
+   To register, complete the following applicable form and send it via
    electronic mail to <IANA@IANA.ORG>.
 
-10.1 IANA registration form for Disposition-Notification-Options header
-   parameter names
+10.1.  Disposition-Notification-Options header parameter names
 
    A registration for a Disposition-Notification-Options header
    parameter name MUST include the following information:
 
    (a) The proposed parameter name.
 
    (b) The syntax for parameter values, specified using BNF, ABNF,
    regular expressions, or other non-ambiguous language.

(c) If parameter values are not composed entirely of graphic characters from the US-ASCII repertoire, a specification for how they are to be encoded as graphic US-ASCII characters in a Disposition-Notification-Options header.

(d) A reference to a standards track RFC or experimental RFC approved by the IESG that describes the semantics of the parameter values.

• 10.2 IANA registration form for disposition modifer names +10.2. Disposition modifier names +
• A registration for a disposition-modifier name MUST include + A registration for a disposition-modifier name (used in the + Disposition field of a message/disposition-notification) MUST include the following information:

(a) The proposed disposition-modifier name.

 
-   (b) A reference to a standards track RFC or experimental RFC approved
-   by the IESG that describes the semantics of the disposition modifier.
+   (b)  A reference to a standards track RFC or experimental RFC
+        approved by the IESG that describes the semantics of the
+        disposition modifier.
 
-10.3 IANA registration form for MDN extension field names
+10.3.  MDN extension field names

A registration for an MDN extension field name MUST include the following information:

(a) The proposed extension field name.

• (b) The syntax for extension values, specified using BNF, ABNF,
• regular expressions, or other non-ambiguous language. + (b) The syntax for extension values, specified using BNF, ABNF, + regular expressions, or other non-ambiguous language.

   
  -   (c) If extension field values are not composed entirely of graphic
  -   characters from the US-ASCII repertoire, a specification for how they
  -   are to be encoded as graphic US-ASCII characters in a Disposition-
  -   Notification-Options header.
  +   (c)  If extension-field values are not composed entirely of graphic
  +        characters from the US-ASCII repertoire, a specification for how
  +        they are to be encoded as graphic US-ASCII characters in a
  +        Disposition-Notification-Options header.
   
  -   (d) A reference to a standards track RFC or experimental RFC approved
  -   by the IESG that describes the semantics of the extension field.
  +   (d)  A reference to a standards track RFC or experimental RFC
  +        approved by the IESG that describes the semantics of the
  +        extension field.

11. Acknowledgments

+ This document is an updated version of the original document written + by Roger Fajman. His contributions to the definition of Message + Disposition Notifications are greatly appreciated. +

• This document is based on the Delivery Status Notifications document, + RFC 2298 was based on the Delivery Status Notifications document
• RFC 1894 [9], by Keith Moore and Greg Vaudreuil. Contributions + [RFC-DSN-FORMAT] by Keith Moore and Greg Vaudreuil. Contributions were made by members of the IETF Receipt Working Group, including
• Harald Alverstrand, Ian Bell, Urs Eppenberger, Claus Andri Faerber, + Harald Alvestrand, Ian Bell, Urs Eppenberger, Claus Andri Faerber, Ned Freed, Jim Galvin, Carl Hage, Mike Lake, Keith Moore, Paul
• Overell, Pete Resnick, Chuck Shih. + Overell, Pete Resnick, and Chuck Shih.

12. References

+12.1. Normative References

• [1] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
• August 1982. + [RFC-SMTP] Klensin, J., Ed., "Simple Mail Transfer Protocol", + RFC 2821, April 2001.

   
  -   [2]   Crocker, D., "Standard for the Format of ARPA Internet Text
  -         Messages", STD 11, RFC 822, August 1982.
  +   [RFC-MSGFMT]      Resnick, P., Ed., "Internet Message Format", RFC
  +                     2822, April 2001.
   
  -   [3]   Braden, R. (ed.), "Requirements for Internet Hosts -
  -         Application and Support", STD 3, RFC 1123, October 1989.
   
  -   [4]   Freed, N., and N. Borenstein, "Multipurpose Internet Mail
  -         Extensions (MIME) Part One:  Format of Internet Message
  -         Bodies", RFC 2045, November 1996.
  +   [RFC-MIME-BODY]   Freed, N. and N. Borenstein, "Multipurpose Internet
  +                     Mail Extensions (MIME) Part One: Format of Internet
  +                     Message Bodies", RFC 2045, November 1996.
   
  -   [5]   Freed, N., and N. Borenstein, "Multipurpose Internet Mail
  -         Extensions (MIME) Part Two:  Media Types", RFC 2046, November
  -         1996.
  +   [RFC-MIME-MEDIA]  Freed, N. and N. Borenstein, "Multipurpose Internet
  +                     Mail Extensions (MIME) Part Two: Media Types", RFC
  +                     2046, November 1996.
   
  -   [6]   Moore, K., "Multipurpose Internet Mail Extensions (MIME) Part
  -         Three:  Message Header Extensions for Non-Ascii Text", RFC
  -         2047, November 1996.
  +   [RFC-MIME-HEADER] Moore, K., "MIME (Multipurpose Internet Mail
  +                     Extensions) Part Three: Message Header Extensions
  +                     for Non-ASCII Text", RFC 2047, November 1996.
   
  -   [7]   Vaudreuil, G., "The Multipart/Report Content Type for the
  -         Reporting of Mail System Administrative Messages", RFC 1892,
  -         January 1996.
  +   [RFC-REPORT]      Vaudreuil, G., "The Multipart/Report Content Type
  +                     for the Reporting of Mail System Administrative
  +                     Messages", RFC 3462, January 2003.
   
  -   [8]   Moore, K., "SMTP Service Extension for Delivery Status
  -         Notifications", RFC 1891, January 1996.
  +   [RFC-DSN-SMTP]    Moore, K., "Simple Mail Transfer Protocol (SMTP)
  +                     Service Extension for Delivery Status
  +                     Notifications", RFC 3461, January 2003.
   
  -   [9]   Moore, K., and G. Vaudreuil, "An Extensible Format for
  -         Delivery Status Notifications, RFC 1894, January 1996. 
  +   [RFC-DSN-FORMAT]  Moore, K., and G. Vaudreuil, "An Extensible Format
  +                     for Delivery Status Notifications (DSNs)", RFC
  +                     3464, January 2003.
  +
  -   [10]  Bradner, S., "Key Words for Use in RFCs to Indicate
  +
  +   [RFC-KEYWORDS]    Bradner, S., "Key Words for Use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119, March 1997.

+12.2. Informative References + + [SEC-SERVICES] Hoffman, P., Ed., "Enhanced Security Services for + S/MIME", RFC 2634, June 1999.

+Appendix A - Changes from RFC 2298 + + The document has new editors. + + The dispositions "denied", and "failed" were removed from the + document reflecting the lack of implementation or usage at this time. + + The disposition modifiers "warning", "superseded", "expired", + "mailbox-terminated" have not seen actual implementation. They have + been deleted from this document. The extension modifier, as of yet + unused, has been retained for future extension. + + General editorial cleanups include spelling, grammar, and consistency + in usage of terms. + + The document has modified BNF for disposition notification options to + eliminate the need for dummy values where not otherwise needed.

• 13. Author's Address +Authors' Addresses

• Roger Fajman
• National Institutes of Health
• Building 12A, Room 3063
• 12 South Drive MSC 5659
• Bethesda, Maryland 20892-5659
• USA

   
  -   EMail:  raf@cu.nih.gov
  -   Phone:  +1 301 402 4265
  -   Fax:    +1 301 480 6241

+ Tony Hansen + AT&T Laboratories + Middletown, NJ 07748 + USA + Voice: +1-732-420-8934 + EMail: tony+rfc3798@maillennium.att.com + + Gregory M. Vaudreuil + Lucent Technologies + 7291 Williamson Rd + Dallas, TX 75214 + USA + Voice: +1 214 823 9325 + EMail: GregV@ieee.org

• 14. Full Copyright Statement

   
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