Page 25

7.  The Received-SPF Header Field

It is RECOMMENDED that SMTP receivers record the result of SPF
processing in the message header.  If an SMTP receiver chooses to do
so, it SHOULD use the "Received-SPF" header field defined here for
each identity that was checked.  This information is intended for the
recipient.  (Information intended for the sender is described in
Section 6.2, Explanation.)

7. Received-SPFヘッダフィールド

SMTP受信者はSPF処理の結果をメッセージヘッダ中に記録することが推奨される（RECOMMENDED）。SMTP受信者が上記の動作を選択する場合は、検査を行った各アイデンティティに対し、本章で定義する“Received-SPF”ヘッダフィールドを使うべきである（SHOULD）。この情報の目的は受信者による使用である（送信者向けの情報については6.2「説明」で記述されている）。

The Received-SPF header field is a trace field (see [RFC2822] Section
3.6.7) and SHOULD be prepended to the existing header, above the
Received: field that is generated by the SMTP receiver.  It MUST
appear above all other Received-SPF fields in the message.  The
header field has the following format:

Received-SPFヘッダフィールドは追跡フィールド（［RFC2822］の3.6.7を参照）であり、既存のヘッダの前、SMTP受信者の生成するReceived：フィールドの上に置くべきである（SHOULD）。また、メッセージ中の他のすべてのReceived-SPFフィールドの上に置かなければならない（MUST）。このヘッダフィールドは以下の形式をとる：

header-field     = "Received-SPF:" [CFWS] result FWS [comment FWS]
                   [ key-value-list ] CRLF
result           = "Pass" / "Fail" / "SoftFail" / "Neutral" /
                   "None" / "TempError" / "PermError"
key-value-list   = key-value-pair *( ";" [CFWS] key-value-pair )
                   [";"]
key-value-pair   = key [CFWS] "=" ( dot-atom / quoted-string )
key              = "client-ip" / "envelope-from" / "helo" /
                   "problem" / "receiver" / "identity" /
                    mechanism / "x-" name / name
identity         = "mailfrom"   ; for the "MAIL FROM" identity
                   / "helo"     ; for the "HELO" identity
                   / name       ; other identities
dot-atom         = <unquoted word as per [RFC2822]>
quoted-string    = <quoted string as per [RFC2822]>
comment          = <comment string as per [RFC2822]>
CFWS             = <comment or folding white space as per [RFC2822]>
FWS              = <folding white space as per [RFC2822]>
CRLF             = <standard end-of-line token as per [RFC2822]>

header-field     =  "Received-SPF:" [CFWS] result FWS [comment FWS]
                    [ key-value-list ] CRLF
result           =  "Pass" / "Fail" / "SoftFail" / "Neutral" /
                    "None" / "TempError" / "PermError"
key-value-list   =  key-value-pair *( ";" ［CFWS］ key-value-pair )
                    ［";"］
key-value-pair   =  key [CFWS] "=" ( dot-atom / quoted-string )
key              =  "client-ip" / "envelope-from" / "helo" /
                    "problem" / "receiver" / "identity" /
                     mechanism / "x-" name / name
identity         =  "mailfrom"   ; “MAIL FROM”アイデンティティ用
                    / "helo"     ; “HELO”アイデンティティ用
                    / name       ; その他のアイデンティティ
dot-atom         = <unquoted word as per [RFC2822]>　（［RFC2822］仕様の非引用語）
quoted-string    = <quoted string as per [RFC2822]>　（［RFC2822］仕様の引用文字列）
comment          = <comment string as per [RFC2822]>　（［RFC2822］仕様のコメント文字列）
CFWS             = <comment or folding white space as per [RFC2822]>　（［RFC2822］仕様のコメントまたは多重空白）
FWS              = <folding white space as per [RFC2822]>　（［RFC2822］仕様の多重空白）
CRLF             = <standard end-of-line token as per [RFC2822]>　（［RFC2822］仕様の標準文末トークン）

The header field SHOULD include a "(...)" style <comment> after the
result, conveying supporting information for the result, such as
<ip>, <sender>, and <domain>.

ヘッダフィールドは結果の後に“（…）”という形式の<comment>を入れて、<ip>、<sender>、<domain>などの結果に対するサポート情報を伝えるべきである（SHOULD）。

[Page 25]