Network Working Group                                         D. Kristol
Request for Comments: 2965        Bell Laboratories, Lucent Technologies
Obsoletes: 2109                                              L. Montulli
Category: Standards Track                   , Inc.
                                                            October 2000
                    HTTP State Management Mechanism

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.

この文書は、インターネットコミュニティのため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状態への「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。

Copyright Notice


Copyright (C) The Internet Society (2000). All Rights Reserved.




The IESG notes that this mechanism makes use of the .local top-level domain (TLD) internally when handling host names that don't contain any dots, and that this mechanism might not work in the expected way should an actual .local TLD ever be registered.

IESGは、このメカニズムは、任意のドットを含まないホスト名を処理するときに内部的に.localのトップレベルドメイン(TLD)を利用して、このメカニズムが期待通りに動作しない可能性があります、これまで実際の.local TLDなければならないことと指摘します登録します。



This document specifies a way to create a stateful session with Hypertext Transfer Protocol (HTTP) requests and responses. It describes three new headers, Cookie, Cookie2, and Set-Cookie2, which carry state information between participating origin servers and user agents. The method described here differs from Netscape's Cookie proposal [Netscape], but it can interoperate with HTTP/1.0 user agents that use Netscape's method. (See the HISTORICAL section.)

この文書では、ハイパーテキスト転送プロトコル(HTTP)要求と応答を持つステートフルセッションを作成する方法を指定します。それは、参加オリジンサーバとユーザエージェント間の状態情報を運ぶつの新しいヘッダ、クッキー、Cookie2、およびSet-Cookie2を、説明しています。ここで説明する方法は、Netscapeのクッキーの提案[ネットスケープ]とは異なり、それはNetscapeのメソッドを使用するHTTP / 1.0ユーザエージェントと相互運用することができます。 (HISTORICALセクションを参照してください。)

This document reflects implementation experience with RFC 2109 and obsoletes it.

この文書は、RFC 2109での実装経験を反映して、それを廃止します。


The terms user agent, client, server, proxy, origin server, and http_URL have the same meaning as in the HTTP/1.1 specification [RFC2616]. The terms abs_path and absoluteURI have the same meaning as in the URI Syntax specification [RFC2396].

用語のユーザエージェントは、クライアント、サーバー、プロキシ、オリジンサーバ、およびHTTP_URL HTTP / 1.1仕様書[RFC2616]と同じ意味を持ちます。用語は腹筋_経路とabsoluteURIでは、URIシンタックス仕様[RFC2396]と同じ意味を持ちます。

Host name (HN) means either the host domain name (HDN) or the numeric Internet Protocol (IP) address of a host. The fully qualified domain name is preferred; use of numeric IP addresses is strongly discouraged.


The terms request-host and request-URI refer to the values the client would send to the server as, respectively, the host (but not port) and abs_path portions of the absoluteURI (http_URL) of the HTTP request line. Note that request-host is a HN.


The term effective host name is related to host name. If a host name contains no dots, the effective host name is that name with the string .local appended to it. Otherwise the effective host name is the same as the host name. Note that all effective host names contain at least one dot.


The term request-port refers to the port portion of the absoluteURI (http_URL) of the HTTP request line. If the absoluteURI has no explicit port, the request-port is the HTTP default, 80. The request-port of a cookie is the request-port of the request in which a Set-Cookie2 response header was returned to the user agent.

用語リクエストポートは、HTTPリクエストラインのabsoluteURIで(HTTP_URL)のポート部分を指します。 absoluteURIでは、明示的なポートを有していない場合、リクエストポートがHTTPのデフォルトであり、クッキーの80リクエストポートは、Set-Cookie2レスポンスヘッダは、ユーザーエージェントに戻されたリクエストのリクエストポートです。

Host names can be specified either as an IP address or a HDN string. Sometimes we compare one host name with another. (Such comparisons SHALL be case-insensitive.) Host A's name domain-matches host B's if

ホスト名はIPアドレスまたはHDN文字列として指定することができます。時々、私たちはお互いに一つのホスト名を比較します。 (このような比較は、大文字と小文字を区別しないものでなければならない。)ホストAの名前のドメインマッチホストBさんの場合

* their host name strings string-compare equal; or


* A is a HDN string and has the form NB, where N is a non-empty name string, B has the form .B', and B' is a HDN string. (So, domain-matches but not

* AはHDN文字列であり、Nは非空の名前の文字列で、Bは、フォ​​ーム.B「を有し、そしてB」はHDN文字列であるフォームNBを有しています。 (だから、x.y.comドメインマッチ.Y.comではなく。)

Note that domain-match is not a commutative operation: domain-matches, but not the reverse.


The reach R of a host name H is defined as follows:


* If


- H is the host domain name of a host; and,

- Hはホストのホストドメイン名です。そして、

- H has the form A.B; and

- Hは、フォームA.Bを有します。そして

- A has no embedded (that is, interior) dots; and

- Aには埋め込まれた(すなわち、内部)でドットを有していません。そして

- B has at least one embedded dot, or B is the string "local". then the reach of H is .B.

- Bは、少なくとも1個の埋め込みドットを有し、またはBは、「ローカル」の文字列です。その後、Hのリーチが.Bです。

* Otherwise, the reach of H is H.


For two strings that represent paths, P1 and P2, P1 path-matches P2 if P2 is a prefix of P1 (including the case where P1 and P2 string-compare equal). Thus, the string /tec/waldo path-matches /tec.

二つのパスを表す文字列、P1及びP2は、P1経路マッチP2 P2は(P1およびP2に等しい文字列が、比較ケースを含む)P1の接頭辞である場合。このように、文字列/ TEC /ワルドパス・マッチ/ TEC。

Because it was used in Netscape's original implementation of state management, we will use the term cookie to refer to the state information that passes between an origin server and user agent, and that gets stored by the user agent.


1.1 Requirements

The key words "MAY", "MUST", "MUST NOT", "OPTIONAL", "RECOMMENDED", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT" in this document are to be interpreted as described in RFC 2119 [RFC2119].

キーワード "MAY"、 "MUST"、 "MUST NOT"、 "オプション"、 "推奨"、 "REQUIRED"、 "NOT SHALL"、 "SHOULD" "ものと"、本書である "すべきではありません" RFC 2119 [RFC2119]に記載されているように解釈されます。

2. STATEとセッション

This document describes a way to create stateful sessions with HTTP requests and responses. Currently, HTTP servers respond to each client request without relating that request to previous or subsequent requests; the state management mechanism allows clients and servers that wish to exchange state information to place HTTP requests and responses within a larger context, which we term a "session". This context might be used to create, for example, a "shopping cart", in which user selections can be aggregated before purchase, or a magazine browsing system, in which a user's previous reading affects which offerings are presented.


Neither clients nor servers are required to support cookies. A server MAY refuse to provide content to a client that does not return the cookies it sends.



We describe here a way for an origin server to send state information to the user agent, and for the user agent to return the state information to the origin server. The goal is to have a minimal impact on HTTP and user agents.


3.1 Syntax: General

The two state management headers, Set-Cookie2 and Cookie, have common syntactic properties involving attribute-value pairs. The following grammar uses the notation, and tokens DIGIT (decimal digits), token (informally, a sequence of non-special, non-white space characters), and http_URL from the HTTP/1.1 specification [RFC2616] to describe their syntax.

2つの状態管理ヘッダは、Set-Cookie2とクッキーは、属性と値のペアを含む一般的な構文上の特性を有しています。次の文法は表記法を使用し、その構文を記述するためにHTTP / 1.1仕様書[RFC2616]から数字(桁)、トークン(非特殊、非空白文字の非公式、配列)、およびHTTP_URLトークン。

av-pairs = av-pair *(";" av-pair) av-pair = attr ["=" value] ; optional value attr = token value = token | quoted-string

一対の=オフペア(「;」ペアの)ペア= ATTRの[「=」値]の。オプションの値のattr =トークン値=トークン|引用符で囲まれた文字列

Attributes (names) (attr) are case-insensitive. White space is permitted between tokens. Note that while the above syntax description shows value as optional, most attrs require them.


NOTE: The syntax above allows whitespace between the attribute and the = sign.


3.2 Origin Server Role

3.2.1 General The origin server initiates a session, if it so desires. To do so, it returns an extra response header to the client, Set-Cookie2. (The details follow later.)

3.2.1一般的なオリジンサーバは、セッションを開始し、それならば欲望ので。そのためには、クライアントは、Set-Cookie2に余分なレスポンスヘッダを返します。 (詳細は、後に続きます。)

A user agent returns a Cookie request header (see below) to the origin server if it chooses to continue a session. The origin server MAY ignore it or use it to determine the current state of the session. It MAY send back to the client a Set-Cookie2 response header with the same or different information, or it MAY send no Set-Cookie2 header at all. The origin server effectively ends a session by sending the client a Set-Cookie2 header with Max-Age=0.

それはセッションを継続することを選択した場合、ユーザエージェントは、オリジンサーバに(下記参照)クッキー要求ヘッダを返します。オリジンサーバはそれを無視するか、セッションの現在の状態を判断するためにそれを使用することができます。これは、クライアントに、同じまたは異なる情報を持つSet-Cookie2レスポンスヘッダを送信することができ、またはそれは全くのSet-Cookie2ヘッダを送信しない場合があります。オリジンサーバは、効果的にクライアントにマックス・年齢= 0と設定-Cookie2ヘッダを送信することでセッションを終了します。

Servers MAY return Set-Cookie2 response headers with any response. User agents SHOULD send Cookie request headers, subject to other rules detailed below, with every request.


An origin server MAY include multiple Set-Cookie2 headers in a response. Note that an intervening gateway could fold multiple such headers into a single header.


3.2.2 Set-Cookie2 Syntax The syntax for the Set-Cookie2 response header is


set-cookie = "Set-Cookie2:" cookies cookies = 1#cookie cookie = NAME "=" VALUE *(";" set-cookie-av) NAME = attr VALUE = value set-cookie-av = "Comment" "=" value | "CommentURL" "=" <"> http_URL <"> | "Discard" | "Domain" "=" value | "Max-Age" "=" value | "Path" "=" value | "Port" [ "=" <"> portlist <"> ] | "Secure" | "Version" "=" 1*DIGIT portlist = 1#portnum portnum = 1*DIGIT

セットクッキー= "するSet-Cookie2:" クッキークッキー= 1枚の#クッキークッキー= NAME "=" VALUE×( ";" セットクッキー-AV)NAME = ATTR値=値のSet-Cookie-AV = "コメント" " =」値| "CommentURL" "=" < "> HTTP_URL <"> | 「捨てます」| 「ドメイン」「=」値| 「マックス・エイジ」「=」値| 「パス」、「=」の値| "ポート" [ "=" < ">ポートリスト<">] | |「セキュア」 "バージョン" "=" 1 * DIGITポートリスト= 1#portnumをportnumを= 1 * DIGIT

Informally, the Set-Cookie2 response header comprises the token Set-Cookie2:, followed by a comma-separated list of one or more cookies. Each cookie begins with a NAME=VALUE pair, followed by zero or more semi-colon-separated attribute-value pairs. The syntax for attribute-value pairs was shown earlier. The specific attributes and the semantics of their values follows. The NAME=VALUE attribute-value pair MUST come first in each cookie. The others, if present, can occur in any order. If an attribute appears more than once in a cookie, the client SHALL use only the value associated with the first appearance of the attribute; a client MUST ignore values after the first.

非公式には、Set-Cookie2レスポンスヘッダは、一つ以上のクッキーのカンマ区切りのリストが続く-Cookie2設定トークンを:,含みます。各クッキーは、ゼロまたはそれ以上のセミコロンで区切られた属性値のペアが続く名前=値のペアで始まります。属性と値のペアの構文は、以前に示されました。特定の属性とその値の意味は以下。 NAME = VALUE属性と値のペアは、各クッキーの最初の来なければなりません。他の人は、存在する場合、任意の順序で発生する可能性があります。属性はクッキーで複数回表示された場合、クライアントは属性の最初の出現に関連付けられている値のみを使用しなければなりません。クライアントは、最初の後の値を無視しなければなりません。

The NAME of a cookie MAY be the same as one of the attributes in this specification. However, because the cookie's NAME must come first in a Set-Cookie2 response header, the NAME and its VALUE cannot be confused with an attribute-value pair.


NAME=VALUE REQUIRED. The name of the state information ("cookie") is NAME, and its value is VALUE. NAMEs that begin with $ are reserved and MUST NOT be used by applications.

NAME = VALUE REQUIRED。状態情報(「クッキー」)の名前は、名前であり、その値は値です。 $で始まる名前は予約されており、アプリケーションで使用してはいけません。

The VALUE is opaque to the user agent and may be anything the origin server chooses to send, possibly in a server-selected printable ASCII encoding. "Opaque" implies that the content is of interest and relevance only to the origin server. The content may, in fact, be readable by anyone that examines the Set-Cookie2 header.

VALUEはユーザエージェントに不透明であるとオリジンサーバは、サーバが選択した印刷可能なASCIIエンコーディングでは、おそらく、送信することを選択したものかもしれません。 「不透明」はコンテンツのみをオリジンサーバへの関心と関連性があることを意味します。内容は、実際には、Set-Cookie2ヘッダを調べ、誰でも読めるかもしれません。

Comment=value OPTIONAL. Because cookies can be used to derive or store private information about a user, the value of the Comment attribute allows an origin server to document how it intends to use the cookie. The user can inspect the information to decide whether to initiate or continue a session with this cookie. Characters in value MUST be in UTF-8 encoding. [RFC2279]

コメント= valueオプション。クッキーは、ユーザーの個人情報を引き出すか、保存するために使用することができますので、コメント属性の値は、オリジンサーバが、それはクッキーを使用しようとする方法を文書化することができます。ユーザーはこのクッキーとセッションを開始するか継続するかどうかを決定するための情報を調べることができます。値の文字は、UTF-8エンコーディングである必要があります。 [RFC2279]

CommentURL="http_URL" OPTIONAL. Because cookies can be used to derive or store private information about a user, the CommentURL attribute allows an origin server to document how it intends to use the cookie. The user can inspect the information identified by the URL to decide whether to initiate or continue a session with this cookie.

CommentURL = "HTTP_URL" オプション。クッキーは、ユーザーの個人情報を引き出すか、保存するために使用することができますので、CommentURL属性はオリジンサーバが、それはクッキーを使用しようとする方法を文書化することができます。ユーザーはこのクッキーとセッションを開始または継続するかどうかを決定するURLによって識別される情報を調べることができます。

Discard OPTIONAL. The Discard attribute instructs the user agent to discard the cookie unconditionally when the user agent terminates.


Domain=value OPTIONAL. The value of the Domain attribute specifies the domain for which the cookie is valid. If an explicitly specified value does not start with a dot, the user agent supplies a leading dot.

ドメイン= valueオプション。ドメイン属性の値は、クッキーが有効なドメインを指定します。明示的に指定された値がドットで起動しない場合、ユーザエージェントは先頭にドットを供給します。

Max-Age=value OPTIONAL. The value of the Max-Age attribute is delta-seconds, the lifetime of the cookie in seconds, a decimal non-negative integer. To handle cached cookies correctly, a client SHOULD calculate the age of the cookie according to the age calculation rules in the HTTP/1.1 specification [RFC2616]. When the age is greater than delta-seconds seconds, the client SHOULD discard the cookie. A value of zero means the cookie SHOULD be discarded immediately.

マックス・エイジ= valueオプション。マックス・年齢属性の値は、デルタ秒、秒単位でクッキーの寿命、小数非負の整数です。正しくキャッシュされたクッキーを処理するには、クライアントはHTTP / 1.1仕様書[RFC2616]で年齢計算ルールに従ってクッキーの年齢を計算する必要があります。年齢はデルタ秒の秒よりも大きい場合、クライアントがクッキーを破棄すべきです。ゼロの値は、クッキーはすぐに破棄されるべきであることを意味します。

Path=value OPTIONAL. The value of the Path attribute specifies the subset of URLs on the origin server to which this cookie applies.

パス= valueオプション。 Path属性の値は、このクッキーが適用されるオリジンサーバ上のURLのサブセットを指定します。

Port[="portlist"] OPTIONAL. The Port attribute restricts the port to which a cookie may be returned in a Cookie request header. Note that the syntax REQUIREs quotes around the OPTIONAL portlist even if there is only one portnum in portlist.

ポート[= "ポートリスト"]オプション。ポート属性は、クッキーは、クッキー要求ヘッダーに戻すことができるれるポートを制限します。ポートリストで唯一のportNumがあっても、構文はオプションポートリストの前後に引用符が必要であることに注意してください。

Secure OPTIONAL. The Secure attribute (with no value) directs the user agent to use only (unspecified) secure means to contact the origin server whenever it sends back this cookie, to protect the confidentially and authenticity of the information in the cookie.

オプション固定します。 (値なし)セキュア属性は、クッキーに機密にし、情報の信憑性を保護するために、このクッキーを送り返したときに、オリジンサーバに接続するための唯一の(未指定)安全な手段を使用するユーザーエージェントに指示します。

The user agent (possibly with user interaction) MAY determine what level of security it considers appropriate for "secure" cookies. The Secure attribute should be considered security advice from the server to the user agent, indicating that it is in the session's interest to protect the cookie contents. When it sends a "secure" cookie back to a server, the user agent SHOULD use no less than the same level of security as was used when it received the cookie from the server.


Version=value REQUIRED. The value of the Version attribute, a decimal integer, identifies the version of the state management specification to which the cookie conforms. For this specification, Version=1 applies.

バージョン=値が必要です。バージョン属性は、10進整数の値は、クッキーが準拠する状態管理仕様のバージョンを識別する。この仕様のため、バージョン= 1が適用されます。

3.2.3 Controlling Caching An origin server must be cognizant of the effect of possible caching of both the returned resource and the Set-Cookie2 header. Caching "public" documents is desirable. For example, if the origin server wants to use a public document such as a "front door" page as a sentinel to indicate the beginning of a session for which a Set-Cookie2 response header must be generated, the page SHOULD be stored in caches "pre-expired" so that the origin server will see further requests. "Private documents", for example those that contain information strictly private to a session, SHOULD NOT be cached in shared caches.

3.2.3キャッシングの制御オリジンサーバは返されたリソースとSet-Cookie2ヘッダの両方の可能性のあるキャッシュの効果を認識しなければなりません。 「パブリック」のドキュメントをキャッシュすることが望ましいです。オリジンサーバがセットCookie2レスポンスヘッダを生成する必要のあるセッションの開始を示すために、センチネルような「フロントドア」ページなどの公共の文書を使用したい場合たとえば、ページがキャッシュに格納する必要がありますオリジンサーバがさらに要求を確認するように「事前期限切れ」。例セッションに厳密に個人情報が含まれているもののために「プライベート文書」は、共有キャッシュにキャッシュされるべきではありません。

If the cookie is intended for use by a single user, the Set-Cookie2 header SHOULD NOT be cached. A Set-Cookie2 header that is intended to be shared by multiple users MAY be cached.


The origin server SHOULD send the following additional HTTP/1.1 response headers, depending on circumstances:

オリジンサーバは、状況に応じて、以下の追加のHTTP / 1.1応答ヘッダを送信する必要があります。

* To suppress caching of the Set-Cookie2 header:


Cache-control: no-cache="set-cookie2"

キャッシュコントロール:キャッシュなし= "するSet-Cookie2"

and one of the following:


* To suppress caching of a private document in shared caches:


Cache-control: private


* To allow caching of a document and require that it be validated before returning it to the client:


Cache-Control: must-revalidate, max-age=0

Cache-Control:-再検証する必要があり、最大エージング= 0

* To allow caching of a document, but to require that proxy caches (not user agent caches) validate it before returning it to the client:


Cache-Control: proxy-revalidate, max-age=0

Cache-Control:プロキシ再検証、最大エージング= 0

* To allow caching of a document and request that it be validated before returning it to the client (by "pre-expiring" it):


Cache-control: max-age=0

キャッシュコントロール:最大年齢= 0

Not all caches will revalidate the document in every case.


HTTP/1.1 servers MUST send Expires: old-date (where old-date is a date long in the past) on responses containing Set-Cookie2 response headers unless they know for certain (by out of band means) that there are no HTTP/1.0 proxies in the response chain. HTTP/1.1 servers MAY send other Cache-Control directives that permit caching by HTTP/1.1 proxies in addition to the Expires: old-date directive; the Cache-Control directive will override the Expires: old-date for HTTP/1.1 proxies.

HTTP / 1.1のサーバーに送信しなければならない有効期限:古い日付(古い日付が過去に長い日付である場合)に設定し-Cookie2レスポンスヘッダを含む応答に、彼らは確かに知っていない限り、(バンドの外で意味)は、HTTPがないこと/応答チェーンで1.0のプロキシ。 HTTP / 1.1サーバは他に/ HTTPで1.1プロキシをキャッシュを許可する他のCache-Controlディレクティブを送信することは、有効期限:古い日付のディレクティブを、 HTTP / 1.1プロキシの古い日付を:のCache-Controlディレクティブは、有効期限を上書きします。

3.3 User Agent Role

3.3.1 Interpreting Set-Cookie2 The user agent keeps separate track of state information that arrives via Set-Cookie2 response headers from each origin server (as distinguished by name or IP address and port). The user agent MUST ignore attribute-value pairs whose attribute it does not recognize. The user agent applies these defaults for optional attributes that are missing:


Discard The default behavior is dictated by the presence or absence of a Max-Age attribute.


Domain Defaults to the effective request-host. (Note that because there is no dot at the beginning of effective request-host, the default Domain can only domain-match itself.)

効果的なリクエストホストへのドメインの既定値。 (効果的なリクエストホストの先頭にドットが存在しないため、デフォルトのドメインのみが自身をドメインと一致することに注意してください。)

Max-Age The default behavior is to discard the cookie when the user agent exits.


Path Defaults to the path of the request URL that generated the Set-Cookie2 response, up to and including the right-most /.


Port The default behavior is that a cookie MAY be returned to any request-port.


Secure If absent, the user agent MAY send the cookie over an insecure channel.


3.3.2 Rejecting Cookies To prevent possible security or privacy violations, a user agent rejects a cookie according to rules below. The goal of the rules is to try to limit the set of servers for which a cookie is valid, based on the values of the Path, Domain, and Port attributes and the request-URI, request-host and request-port.


A user agent rejects (SHALL NOT store its information) if the Version attribute is missing. Moreover, a user agent rejects (SHALL NOT store its information) if any of the following is true of the attributes explicitly present in the Set-Cookie2 response header:


* The value for the Path attribute is not a prefix of the request-URI.

* Path属性の値は、リクエストURIの接頭辞ではありません。

* The value for the Domain attribute contains no embedded dots, and the value is not .local.


* The effective host name that derives from the request-host does not domain-match the Domain attribute.


* The request-host is a HDN (not IP address) and has the form HD, where D is the value of the Domain attribute, and H is a string that contains one or more dots.


* The Port attribute has a "port-list", and the request-port was not in the list.




* A Set-Cookie2 from request-host for would be rejected, because H is y.x and contains a dot.

Hがy.xで、ドットが含まれているため、*リクエストホストからドメイン= .foo.comをのためのSet-Cookie2は、拒否されます。

* A Set-Cookie2 from request-host for would be accepted.

*ドメイン= .foo.comを要求 - ホストからのSet-Cookie2は受け入れられます。

* A Set-Cookie2 with or, will always be rejected, because there is no embedded dot.

*ドメインを持つSet-Cookie2 = .comやドメイン= .COM。何埋め込まドットが存在しないため、常に、拒否されます。

* A Set-Cookie2 with will be accepted, and the value for Domain will be taken to be, because a dot gets prepended to the value.

*ドメインを持つSet-Cookie2 = ajax.comは受け入れられますし、ドットが値の前に追加されますので、ドメインの価値は、.ajax.comであると解釈されます。

* A Set-Cookie2 with Port="80,8000" will be accepted if the request was made to port 80 or 8000 and will be rejected otherwise.


* A Set-Cookie2 from request-host example for Domain=.local will be accepted, because the effective host name for the request-host is example.local, and example.local domain-matches .local.

リクエストホストのための有効なホスト名がexample.localあるので* .localのドメイン=の要求ホスト例からのSet-Cookie2は、受理され、example.localドメインマッチは.local。

3.3.3 Cookie Management If a user agent receives a Set-Cookie2 response header whose NAME is the same as that of a cookie it has previously stored, the new cookie supersedes the old when: the old and new Domain attribute values compare equal, using a case-insensitive string-compare; and, the old and new Path attribute values string-compare equal (case-sensitive). However, if the Set-Cookie2 has a value for Max-Age of zero, the (old and new) cookie is discarded. Otherwise a cookie persists (resources permitting) until whichever happens first, then gets discarded: its Max-Age lifetime is exceeded; or, if the Discard attribute is set, the user agent terminates the session.


Because user agents have finite space in which to store cookies, they MAY also discard older cookies to make space for newer ones, using, for example, a least-recently-used algorithm, along with constraints on the maximum number of cookies that each origin server may set.


If a Set-Cookie2 response header includes a Comment attribute, the user agent SHOULD store that information in a human-readable form with the cookie and SHOULD display the comment text as part of a cookie inspection user interface.


If a Set-Cookie2 response header includes a CommentURL attribute, the user agent SHOULD store that information in a human-readable form with the cookie, or, preferably, SHOULD allow the user to follow the http_URL link as part of a cookie inspection user interface.


The cookie inspection user interface may include a facility whereby a user can decide, at the time the user agent receives the Set-Cookie2 response header, whether or not to accept the cookie. A potentially confusing situation could arise if the following sequence occurs:


* the user agent receives a cookie that contains a CommentURL attribute;


* the user agent's cookie inspection interface is configured so that it presents a dialog to the user before the user agent accepts the cookie;


* the dialog allows the user to follow the CommentURL link when the user agent receives the cookie; and,


* when the user follows the CommentURL link, the origin server (or another server, via other links in the returned content) returns another cookie.


The user agent SHOULD NOT send any cookies in this context. The user agent MAY discard any cookie it receives in this context that the user has not, through some user agent mechanism, deemed acceptable.


User agents SHOULD allow the user to control cookie destruction, but they MUST NOT extend the cookie's lifetime beyond that controlled by the Discard and Max-Age attributes. An infrequently-used cookie may function as a "preferences file" for network applications, and a user may wish to keep it even if it is the least-recently-used cookie. One possible implementation would be an interface that allows the permanent storage of a cookie through a checkbox (or, conversely, its immediate destruction).


Privacy considerations dictate that the user have considerable control over cookie management. The PRIVACY section contains more information.


3.3.4 Sending Cookies to the Origin Server When it sends a request to an origin server, the user agent includes a Cookie request header if it has stored cookies that are applicable to the request, based on


* the request-host and request-port;


* the request-URI;


* the cookie's age.


The syntax for the header is:


cookie = "Cookie:" cookie-version 1*((";" | ",") cookie-value) cookie-value = NAME "=" VALUE [";" path] [";" domain] [";" port] cookie-version = "$Version" "=" value NAME = attr VALUE = value path = "$Path" "=" value domain = "$Domain" "=" value port = "$Port" [ "=" <"> value <"> ]

クッキー= "クッキー" クッキーバージョン1 *(( ";" | " ")クッキー値)クッキー値= NAME "=" VALUEの[";"道] [";"ドメイン]、[ ";"ポート]クッキーバージョン= "$バージョン" "=" 値NAME = attrの値=値パス= "$パス" "=" 値ドメイン= "$ドメイン" "=" 値ポート= "$ポート" [ "=" < ">値<">]

The value of the cookie-version attribute MUST be the value from the Version attribute of the corresponding Set-Cookie2 response header. Otherwise the value for cookie-version is 0. The value for the path attribute MUST be the value from the Path attribute, if one was present, of the corresponding Set-Cookie2 response header. Otherwise the attribute SHOULD be omitted from the Cookie request header. The value for the domain attribute MUST be the value from the Domain attribute, if one was present, of the corresponding Set-Cookie2 response header. Otherwise the attribute SHOULD be omitted from the Cookie request header.


The port attribute of the Cookie request header MUST mirror the Port attribute, if one was present, in the corresponding Set-Cookie2 response header. That is, the port attribute MUST be present if the Port attribute was present in the Set-Cookie2 header, and it MUST have the same value, if any. Otherwise, if the Port attribute was absent from the Set-Cookie2 header, the attribute likewise MUST be omitted from the Cookie request header.


Note that there is neither a Comment nor a CommentURL attribute in the Cookie request header corresponding to the ones in the Set-Cookie2 response header. The user agent does not return the comment information to the origin server.


The user agent applies the following rules to choose applicable cookie-values to send in Cookie request headers from among all the cookies it has received.


Domain Selection The origin server's effective host name MUST domain-match the Domain attribute of the cookie.


Port Selection There are three possible behaviors, depending on the Port attribute in the Set-Cookie2 response header:


1. By default (no Port attribute), the cookie MAY be sent to any port.


2. If the attribute is present but has no value (e.g., Port), the cookie MUST only be sent to the request-port it was received from.


3. If the attribute has a port-list, the cookie MUST only be returned if the new request-port is one of those listed in port-list.


Path Selection The request-URI MUST path-match the Path attribute of the cookie.

パス選択要求-URI MUSTパス一致クッキーのPath属性を。

Max-Age Selection Cookies that have expired should have been discarded and thus are not forwarded to an origin server.


If multiple cookies satisfy the criteria above, they are ordered in the Cookie header such that those with more specific Path attributes precede those with less specific. Ordering with respect to other attributes (e.g., Domain) is unspecified.


Note: For backward compatibility, the separator in the Cookie header is semi-colon (;) everywhere. A server SHOULD also accept comma (,) as the separator between cookie-values for future compatibility.


3.3.5 Identifying What Version is Understood: Cookie2 The Cookie2 request header facilitates interoperation between clients and servers that understand different versions of the cookie specification. When the client sends one or more cookies to an origin server, if at least one of those cookies contains a $Version attribute whose value is different from the version that the client understands, then the client MUST also send a Cookie2 request header, the syntax for which is


cookie2 = "Cookie2:" cookie-version

cookie2 = "Cookie2:" クッキーバージョン

Here the value for cookie-version is the highest version of cookie specification (currently 1) that the client understands. The client needs to send at most one such request header per request.


3.3.6 Sending Cookies in Unverifiable Transactions Users MUST have control over sessions in order to ensure privacy. (See PRIVACY section below.) To simplify implementation and to prevent an additional layer of complexity where adequate safeguards exist, however, this document distinguishes between transactions that are verifiable and those that are unverifiable. A transaction is verifiable if the user, or a user-designated agent, has the option to review the request-URI prior to its use in the transaction. A transaction is unverifiable if the user does not have that option. Unverifiable transactions typically arise when a user agent automatically requests inlined or embedded entities or when it resolves redirection (3xx) responses from an origin server. Typically the origin transaction, the transaction that the user initiates, is verifiable, and that transaction may directly or indirectly induce the user agent to make unverifiable transactions.

検証不能トランザクションのユーザーが3.3.6送信するクッキーは、プライバシーを確​​保するために、セッションを制御していなければなりません。 (以下プライバシーを参照してください。)実装を簡単にするために、適切な保護手段が存在する複雑さの追加の層を防止するために、しかし、この文書は、検証及び検証不可能であるものであるトランザクションを区別する。ユーザー、またはユーザーが指定したエージェントは、トランザクションでの使用に先立って、リクエストURIを確認するためのオプションを持っている場合、トランザクションが検証可能です。ユーザーがそのオプションを持っていない場合、取引は検証不可能です。ユーザエージェントが自動的にインライン化または埋め込まれたエンティティを要求したときか、それがオリジンサーバからリダイレクト(3xxの)応答を解決する際に検証不可能なトランザクションは、一般的に発生します。通常、原点トランザクション、ユーザーが開始したトランザクションは、検証可能で、そのトランザクションは、直接的または間接的に証明できない取引を行うためにユーザーエージェントを誘導することができます。

An unverifiable transaction is to a third-party host if its request-host U does not domain-match the reach R of the request-host O in the origin transaction.


When it makes an unverifiable transaction, a user agent MUST disable all cookie processing (i.e., MUST NOT send cookies, and MUST NOT accept any received cookies) if the transaction is to a third-party host.


This restriction prevents a malicious service author from using unverifiable transactions to induce a user agent to start or continue a session with a server in a different domain. The starting or continuation of such sessions could be contrary to the privacy expectations of the user, and could also be a security problem.


User agents MAY offer configurable options that allow the user agent, or any autonomous programs that the user agent executes, to ignore the above rule, so long as these override options default to "off".


(N.B. Mechanisms may be proposed that will automate overriding the third-party restrictions under controlled conditions.)


Many current user agents already provide a review option that would render many links verifiable. For instance, some user agents display the URL that would be referenced for a particular link when the mouse pointer is placed over that link. The user can therefore determine whether to visit that site before causing the browser to do so. (Though not implemented on current user agents, a similar technique could be used for a button used to submit a form -- the user agent could display the action to be taken if the user were to select that button.) However, even this would not make all links verifiable; for example, links to automatically loaded images would not normally be subject to "mouse pointer" verification.

現在の多くのユーザエージェントは、すでに検証多くのリンクをレンダリングするでしょうレビューオプションを提供します。例えば、いくつかのユーザエージェントは、マウスポインタがそのリンク上に配置されたときに、特定のリンクのために参照されるURLを表示します。したがって、ユーザは、これを行うには、ブラウザの原因となる前に、そのサイトを訪問するかどうかを判断することができます。 (現在のユーザーエージェントに実装されていないが、同様の技術がフォームを送信するためのボタンを使用することができる - 。ユーザーがそのボタンを選択した場合、ユーザーエージェントが取るべきアクションを表示することができます)しかし、これでも希望すべてのリンクは検証しません。例えば、リンクが自動的にロードされた画像は、通常、「マウスポインタ」検証の対象ではありませんします。

Many user agents also provide the option for a user to view the HTML source of a document, or to save the source to an external file where it can be viewed by another application. While such an option does provide a crude review mechanism, some users might not consider it acceptable for this purpose.



A user agent returns much of the information in the Set-Cookie2 header to the origin server when the request-URI path-matches the Path attribute of the cookie. When it receives a Cookie header, the origin server SHOULD treat cookies with NAMEs whose prefix is $ specially, as an attribute for the cookie.


3.5 Caching Proxy Role

One reason for separating state information from both a URL and document content is to facilitate the scaling that caching permits. To support cookies, a caching proxy MUST obey these rules already in the HTTP specification:

URLおよびドキュメントのコンテンツの両方から状態情報を分離するための一つの理由は、スケーリングそのキャッシュ許可を容易にすることです。 Cookieをサポートするために、キャッシュプロキシは、HTTP仕様で、すでにこれらのルールに従わなければなりません:

* Honor requests from the cache, if possible, based on cache validity rules.


* Pass along a Cookie request header in any request that the proxy must make of another server.


* Return the response to the client. Include any Set-Cookie2 response header.


* Cache the received response subject to the control of the usual headers, such as Expires,


Cache-control: no-cache




Cache-control: private


* Cache the Set-Cookie2 subject to the control of the usual header,


Cache-control: no-cache="set-cookie2"

キャッシュコントロール:キャッシュなし= "するSet-Cookie2"

(The Set-Cookie2 header should usually not be cached.)


Proxies MUST NOT introduce Set-Cookie2 (Cookie) headers of their own in proxy responses (requests).


4.1 Example 1

Most detail of request and response headers has been omitted. Assume the user agent has no stored cookies.


1. User Agent -> Server
1.ユーザーエージェント - >サーバー

POST /acme/login HTTP/1.1 [form data]

POST / ACME /ログインHTTP / 1.1 [フォームデータ]

User identifies self via a form.


2. Server -> User Agent
2. [サーバー] - > [ユーザーエージェント

HTTP/1.1 200 OK Set-Cookie2: Customer="WILE_E_COYOTE"; Version="1"; Path="/acme"

HTTP / 1.1 200 OKのSet-Cookie2:カスタマー= "WILE_E_COYOTE"。バージョン= "1";パス= "/ ACME"

Cookie reflects user's identity.


3. User Agent -> Server
3.ユーザーエージェント - >サーバー

POST /acme/pickitem HTTP/1.1 Cookie: $Version="1"; Customer="WILE_E_COYOTE"; $Path="/acme" [form data]

POST / ACME / pickitem HTTP / 1.1クッキー:$バージョン= "1";カスタマー=「WILE_E_COYOTE」。 $ PATH = "/ ACME" [フォームデータ]

User selects an item for "shopping basket".


4. Server -> User Agent
4.サーバー - >ユーザーエージェント

HTTP/1.1 200 OK Set-Cookie2: Part_Number="Rocket_Launcher_0001"; Version="1"; Path="/acme"

HTTP / 1.1 200 OKのSet-Cookie2:PART_NUMBER = "Rocket_Launcher_0001"。バージョン= "1";パス= "/ ACME"

Shopping basket contains an item.


5. User Agent -> Server
5.ユーザーエージェント - >サーバー
        POST /acme/shipping HTTP/1.1
        Cookie: $Version="1";
                Customer="WILE_E_COYOTE"; $Path="/acme";
                Part_Number="Rocket_Launcher_0001"; $Path="/acme"
        [form data]

User selects shipping method from form.


6. Server -> User Agent
6.サーバー - >ユーザーエージェント

HTTP/1.1 200 OK Set-Cookie2: Shipping="FedEx"; Version="1"; Path="/acme"

HTTP / 1.1 200 OKのSet-Cookie2:送料= "フェデックス"。バージョン= "1";パス= "/ ACME"

New cookie reflects shipping method.


7. User Agent -> Server
7.ユーザーエージェント - >サーバー
        POST /acme/process HTTP/1.1
        Cookie: $Version="1";
                Customer="WILE_E_COYOTE"; $Path="/acme";
                Part_Number="Rocket_Launcher_0001"; $Path="/acme";
                Shipping="FedEx"; $Path="/acme"
        [form data]

User chooses to process order.


8. Server -> User Agent
8.サーバー - >ユーザーエージェント

HTTP/1.1 200 OK

HTTP / 1.1 200 OK

Transaction is complete.


The user agent makes a series of requests on the origin server, after each of which it receives a new cookie. All the cookies have the same Path attribute and (default) domain. Because the request-URIs all path-match /acme, the Path attribute of each cookie, each request contains all the cookies received so far.

ユーザエージェントは、それが新しいクッキーを受け取るそれぞれの後に、オリジンサーバ上の一連の要求を行います。すべてのクッキーは同じPath属性と(デフォルト)ドメインを持っています。リクエストURIのすべてのパスの一致/ ACMEので、各クッキーのPath属性は、各要求は、これまでに受信したすべてのクッキーが含まれています。

4.2 Example 2

This example illustrates the effect of the Path attribute. All detail of request and response headers has been omitted. Assume the user agent has no stored cookies.


Imagine the user agent has received, in response to earlier requests, the response headers


Set-Cookie2: Part_Number="Rocket_Launcher_0001"; Version="1"; Path="/acme"

PART_NUMBER = "Rocket_Launcher_0001";:-Cookie2を設定します。バージョン= "1";パス= "/ ACME"



Set-Cookie2: Part_Number="Riding_Rocket_0023"; Version="1"; Path="/acme/ammo"

PART_NUMBER = "Riding_Rocket_0023";:-Cookie2を設定します。バージョン= "1";パス= "/ ACME /弾薬"

A subsequent request by the user agent to the (same) server for URLs of the form /acme/ammo/... would include the following request header:

フォーム/ ACME /弾薬のURLに対する(同じ)サーバへのユーザエージェントによって後続の要求は、/ ...以下のリクエストヘッダを含むであろう。

   Cookie: $Version="1";
           Part_Number="Riding_Rocket_0023"; $Path="/acme/ammo";
           Part_Number="Rocket_Launcher_0001"; $Path="/acme"

Note that the NAME=VALUE pair for the cookie with the more specific Path attribute, /acme/ammo, comes before the one with the less specific Path attribute, /acme. Further note that the same cookie name appears more than once.

より具体的なPath属性、/ ACME /弾薬を持つCookieのNAME = VALUEペアは、あまり具体的なPath属性、/ ACMEと1の前に来ることに注意してください。また、同じクッキー名が複数回表示されることを確認します。

A subsequent request by the user agent to the (same) server for a URL of the form /acme/parts/ would include the following request header:

フォーム/ ACME /部品/のURLのための(同じ)サーバへのユーザエージェントによって後続の要求は、次のリクエストヘッダを含むであろう。

Cookie: $Version="1"; Part_Number="Rocket_Launcher_0001"; $Path="/acme"

クッキー:$バージョン= "1"; PART_NUMBER = "Rocket_Launcher_0001"。 $ PATH = "/ ACME"

Here, the second cookie's Path attribute /acme/ammo is not a prefix of the request URL, /acme/parts/, so the cookie does not get forwarded to the server.

ここで、第2のクッキーのパス属性/ ACME /弾薬は、リクエストURL、/ ACME /部品/の接頭辞ではありませんので、クッキーはサーバに転送されません。


Here we provide guidance on likely or desirable details for an origin server that implements state management.


5.1 Set-Cookie2 Content

An origin server's content should probably be divided into disjoint application areas, some of which require the use of state information. The application areas can be distinguished by their request URLs. The Set-Cookie2 header can incorporate information about the application areas by setting the Path attribute for each one.


The session information can obviously be clear or encoded text that describes state. However, if it grows too large, it can become unwieldy. Therefore, an implementor might choose for the session information to be a key to a server-side resource. Of course, using a database creates some problems that this state management specification was meant to avoid, namely:


1. keeping real state on the server side;

2. how and when to garbage-collect the database entry, in case the user agent terminates the session by, for example, exiting.


5.2 Stateless Pages

Caching benefits the scalability of WWW. Therefore it is important to reduce the number of documents that have state embedded in them inherently. For example, if a shopping-basket-style application always displays a user's current basket contents on each page, those pages cannot be cached, because each user's basket's contents would be different. On the other hand, if each page contains just a link that allows the user to "Look at My Shopping Basket", the page can be cached.


5.3 Implementation Limits

Practical user agent implementations have limits on the number and size of cookies that they can store. In general, user agents' cookie support should have no fixed limits. They should strive to store as many frequently-used cookies as possible. Furthermore, general-use user agents SHOULD provide each of the following minimum capabilities individually, although not necessarily simultaneously:


* at least 300 cookies


* at least 4096 bytes per cookie (as measured by the characters that comprise the cookie non-terminal in the syntax description of the Set-Cookie2 header, and as received in the Set-Cookie2 header)


* at least 20 cookies per unique host or domain name


User agents created for specific purposes or for limited-capacity devices SHOULD provide at least 20 cookies of 4096 bytes, to ensure that the user can interact with a session-based origin server.


The information in a Set-Cookie2 response header MUST be retained in its entirety. If for some reason there is inadequate space to store the cookie, it MUST be discarded, not truncated.


Applications should use as few and as small cookies as possible, and they should cope gracefully with the loss of a cookie.


5.3.1 Denial of Service Attacks User agents MAY choose to set an upper bound on the number of cookies to be stored from a given host or domain name or on the size of the cookie information. Otherwise a malicious server could attempt to flood a user agent with many cookies, or large cookies, on successive responses, which would force out cookies the user agent had received from other servers. However, the minima specified above SHOULD still be supported.



Informed consent should guide the design of systems that use cookies. A user should be able to find out how a web site plans to use information in a cookie and should be able to choose whether or not those policies are acceptable. Both the user agent and the origin server must assist informed consent.


6.1 User Agent Control

An origin server could create a Set-Cookie2 header to track the path of a user through the server. Users may object to this behavior as an intrusive accumulation of information, even if their identity is not evident. (Identity might become evident, for example, if a user subsequently fills out a form that contains identifying information.) This state management specification therefore requires that a user agent give the user control over such a possible intrusion, although the interface through which the user is given this control is left unspecified. However, the control mechanisms provided SHALL at least allow the user

オリジンサーバは、サーバを介してユーザのパスを追跡するには、Set-Cookie2ヘッダを作成することができます。ユーザーは、自分の身元が明らかでない場合でも、情報の侵入蓄積としてこの行動に反対することがあります。 (ユーザがその後識別情報を含むフォームを記入する場合、Identityは、例えば、明らかになるかもしれない。)この状態管理仕様は、従ってもののインターフェースを介してユーザ、ユーザエージェントはそのような可能な侵入を介してユーザ制御を与えることが必要この制御は、不特定のままに与えられています。しかし、提供される制御機構は、少なくともユーザを許可しなければなりません

* to completely disable the sending and saving of cookies.


* to determine whether a stateful session is in progress.


* to control the saving of a cookie on the basis of the cookie's Domain attribute.


Such control could be provided, for example, by mechanisms


* to notify the user when the user agent is about to send a cookie to the origin server, to offer the option not to begin a session.


* to display a visual indication that a stateful session is in progress.


* to let the user decide which cookies, if any, should be saved when the user concludes a window or user agent session.


* to let the user examine and delete the contents of a cookie at any time.


A user agent usually begins execution with no remembered state information. It SHOULD be possible to configure a user agent never to send Cookie headers, in which case it can never sustain state with an origin server. (The user agent would then behave like one that is unaware of how to handle Set-Cookie2 response headers.)

ユーザーエージェントは、通常、無思い出し状態情報と実行を開始します。オリジンサーバとの状態を維持することはできません、その場合にはCookieヘッダを送信しないように決してユーザーエージェントを設定することが可能です。 (ユーザエージェントは、設定し-Cookie2レスポンスヘッダを処理する方法を知らないである1のように振る舞うでしょう。)

When the user agent terminates execution, it SHOULD let the user discard all state information. Alternatively, the user agent MAY ask the user whether state information should be retained; the default should be "no". If the user chooses to retain state information, it would be restored the next time the user agent runs.


NOTE: User agents should probably be cautious about using files to store cookies long-term. If a user runs more than one instance of the user agent, the cookies could be commingled or otherwise corrupted.


6.2 Origin Server Role

An origin server SHOULD promote informed consent by adding CommentURL or Comment information to the cookies it sends. CommentURL is preferred because of the opportunity to provide richer information in a multiplicity of languages.

オリジンサーバはCommentURLを追加することにより、インフォームドコンセントを促進したり、送信するクッキーに情報をコメントすべきです。 CommentURLは、理由の言語の多様で豊かな情報を提供する機会で好ましいです。

6.3 Clear Text

The information in the Set-Cookie2 and Cookie headers is unprotected. As a consequence:


1. Any sensitive information that is conveyed in them is exposed to intruders.


2. A malicious intermediary could alter the headers as they travel in either direction, with unpredictable results.


These facts imply that information of a personal and/or financial nature should only be sent over a secure channel. For less sensitive information, or when the content of the header is a database key, an origin server should be vigilant to prevent a bad Cookie value from causing failures.


A user agent in a shared user environment poses a further risk. Using a cookie inspection interface, User B could examine the contents of cookies that were saved when User A used the machine.


7.1 Protocol Design

The restrictions on the value of the Domain attribute, and the rules concerning unverifiable transactions, are meant to reduce the ways that cookies can "leak" to the "wrong" site. The intent is to restrict cookies to one host, or a closely related set of hosts. Therefore a request-host is limited as to what values it can set for Domain. We consider it acceptable for hosts and to share cookies, but not and


Similarly, a server can set a Path only for cookies that are related to the request-URI.



Proper application design can avoid spoofing attacks from related domains. Consider:


1. User agent makes request to, gets back cookie session_id="1234" and sets the default domain

1.ユーザエージェントは、要求がvictim.cracker.eduできるようになり、「1234」クッキーがsession_id =を取り戻すと、デフォルトのドメインvictim.cracker.eduを設定します。

2. User agent makes request to, gets back cookie session-id="1111", with Domain="".

2.ユーザーエージェントは要求がspoof.cracker.eduになり、クッキードメイン=とセッションID =「1111」、「」を取り戻します。

3. User agent makes request to again, and passes


Cookie: $Version="1"; session_id="1234", $Version="1"; session_id="1111"; $Domain=""

クッキー:$バージョン= "1"; SESSION_ID = "1234"、$バージョン= "1"; SESSION_ID = "1111"; $ドメイン= ""

The server at should detect that the second cookie was not one it originated by noticing that the Domain attribute is not for itself and ignore it.



A user agent SHOULD make every attempt to prevent the sharing of session information between hosts that are in different domains. Embedded or inlined objects may cause particularly severe privacy problems if they can be used to share cookies between disparate hosts. For example, a malicious server could embed cookie information for host in a URI for a CGI on host User agent implementors are strongly encouraged to prevent this sort of exchange whenever possible.


7.4 Cookies For Account Information

While it is common practice to use them this way, cookies are not designed or intended to be used to hold authentication information, such as account names and passwords. Unless such cookies are exchanged over an encrypted path, the account information they contain is highly vulnerable to perusal and theft.



Apart from RFC 2109, three other proposals have been made to accomplish similar goals. This specification began as an amalgam of Kristol's State-Info proposal [DMK95] and Netscape's Cookie proposal [Netscape].

別にRFC 2109から、他の三つの提案が同様の目標を達成するために行われています。この仕様は、クリストルの国家・インフォ提案[DMK95]とNetscapeのクッキー提案[ネットスケープ]のアマルガムとして始まりました。

Brian Behlendorf proposed a Session-ID header that would be user-agent-initiated and could be used by an origin server to track "clicktrails". It would not carry any origin-server-defined state, however. Phillip Hallam-Baker has proposed another client-defined session ID mechanism for similar purposes.

ブライアン・ベエレンドルフは、ユーザーエージェントが開始するだろうと「clicktrails」を追跡するために、オリジンサーバで使用できるセッションIDヘッダを提案しました。しかし、任意の起源・サーバーに定義された状態を運ぶことはないでしょう。フィリップハラム - ベイカーは、同様の目的のために別のクライアントに定義されたセッションIDメカニズムを提案しました。

While both session IDs and cookies can provide a way to sustain stateful sessions, their intended purpose is different, and, consequently, the privacy requirements for them are different. A user initiates session IDs to allow servers to track progress through them, or to distinguish multiple users on a shared machine. Cookies are server-initiated, so the cookie mechanism described here gives users control over something that would otherwise take place without the users' awareness. Furthermore, cookies convey rich, server-selected information, whereas session IDs comprise user-selected, simple information.


9.1 Compatibility with Existing Implementations

Existing cookie implementations, based on the Netscape specification, use the Set-Cookie (not Set-Cookie2) header. User agents that receive in the same response both a Set-Cookie and Set-Cookie2 response header for the same cookie MUST discard the Set-Cookie information and use only the Set-Cookie2 information. Furthermore, a user agent MUST assume, if it received a Set-Cookie2 response header, that the sending server complies with this document and will understand Cookie request headers that also follow this specification.

Netscapeの仕様に基づいて、既存のクッキーの実装は、セット - クッキー(ないように設定-Cookie2)ヘッダを使用します。同じ応答のSet-CookieおよびSet-Cookie情報を破棄してのみセットCookie2情報を使用しなければならない同じクッキーに設定さ-Cookie2レスポンスヘッダの両方で受信ユーザエージェント。また、ユーザエージェントは、それがセット-Cookie2レスポンスヘッダを受信した場合、送信側サーバーは、この文書に準拠していることを、想定しなければならないし、また本明細書に従うCookieリクエストヘッダを理解するであろう。

New cookies MUST replace both equivalent old- and new-style cookies. That is, if a user agent that follows both this specification and Netscape's original specification receives a Set-Cookie2 response header, and the NAME and the Domain and Path attributes match (per the Cookie Management section) a Netscape-style cookie, the Netscape-style cookie MUST be discarded, and the user agent MUST retain only the cookie adhering to this specification.


Older user agents that do not understand this specification, but that do understand Netscape's original specification, will not recognize the Set-Cookie2 response header and will receive and send cookies according to the older specification.


A user agent that supports both this specification and Netscape-style cookies SHOULD send a Cookie request header that follows the older Netscape specification if it received the cookie in a Set-Cookie response header and not in a Set-Cookie2 response header. However, it SHOULD send the following request header as well:


Cookie2: $Version="1"

Cookie2:$バージョン= "1"

The Cookie2 header advises the server that the user agent understands new-style cookies. If the server understands new-style cookies, as well, it SHOULD continue the stateful session by sending a Set-Cookie2 response header, rather than Set-Cookie. A server that does not understand new-style cookies will simply ignore the Cookie2 request header.


9.2 Caching and HTTP/1.0
9.2キャッシングとHTTP / 1.0

Some caches, such as those conforming to HTTP/1.0, will inevitably cache the Set-Cookie2 and Set-Cookie headers, because there was no mechanism to suppress caching of headers prior to HTTP/1.1. This caching can lead to security problems. Documents transmitted by an origin server along with Set-Cookie2 and Set-Cookie headers usually either will be uncachable, or will be "pre-expired". As long as caches obey instructions not to cache documents (following Expires: <a date in the past> or Pragma: no-cache (HTTP/1.0), or Cache-control: no-cache (HTTP/1.1)) uncachable documents present no problem. However, pre-expired documents may be stored in caches. They require validation (a conditional GET) on each new request, but some cache operators loosen the rules for their caches, and sometimes serve expired documents without first validating them. This combination of factors can lead to cookies meant for one user later being sent to another user. The Set-Cookie2 and Set-Cookie headers are stored in the cache, and, although the document is stale (expired), the cache returns the document in response to later requests, including cached headers.

前HTTP / 1.1ヘッダのキャッシュを抑制するための仕組みがなかったので、このようなHTTP / 1.0に準拠したものなど、一部のキャッシュは、必然的には、Set-Cookie2とSet-Cookieのをヘッダをキャッシュします。このキャッシュは、セキュリティ上の問題につながることができます。セットCookie2と一緒にオリジンサーバが送信した文書およびSet-Cookieヘッダを通常どちらかがキャッシュ不可能であるか、または「事前に有効期限が切れた」となります。限り、キャッシュがドキュメントをキャッシュしないよう指示に従うよう(以下有効期限:past>またはプラグマで<a日:キャッシュなし(HTTP / 1.0)、またはキャッシュコントロール:キャッシュなし(HTTP / 1.1))は、本キャッシュ不可能書類問題ない。しかし、事前に期限切れの文書がキャッシュに格納することができます。彼らはそれぞれの新しい要求の検証(条件付きGET)が必要ですが、いくつかのキャッシュのオペレータは、それらのキャッシュのための規則を緩め、そして時には最初にそれらを検証せずに期限切れのドキュメントを提供しています。要因の組み合わせは、後に別のユーザーに送信されている一人のユーザーのために意味のクッキーにつながることができます。ドキュメントが古い(期限切れ)であるが、セット-Cookie2とのSet-Cookieヘッダは、キャッシュは、キャッシュされたヘッダを含むそれ以降の要求に応答して文書を返し、キャッシュに格納され、そしてれます。


This document really represents the collective efforts of the HTTP Working Group of the IETF and, particularly, the following people, in addition to the authors: Roy Fielding, Yaron Goland, Marc Hedlund, Ted Hardie, Koen Holtman, Shel Kaphan, Rohit Khare, Foteos Macrides, David W. Morris.

この文書では、実際に著者に加えて、特に、以下の方々にIETFのHTTPワーキンググループの集団的努力を表し、:ロイ・フィールディング、ヤロンGoland、マルクHedlund、テッドハーディー、公園Holtman、SHEL Kaphan、ロフィット・クヘアを、 Foteos Macrides、デビッドW.モリス。


David M. Kristol Bell Laboratories, Lucent Technologies 600 Mountain Ave. Room 2A-333 Murray Hill, NJ 07974

デイビッドM.クリストルベル研究所、ルーセント・テクノロジーズ600マウンテンアベニュールーム2A-333マレーヒル、NJ 07974

Phone: (908) 582-2250 Fax: (908) 582-1239 EMail:

電話:(908)582-2250ファックス:(908)582-1239 Eメール

Lou Montulli, Inc. 2037 Landings Dr. Mountain View, CA 94301

ルー・モントゥリEpinions.com株式会社2037着陸博士はマウンテンビュー、CA 94301




[DMK95] Kristol, D.M., "Proposed HTTP State-Info Mechanism", available at <>, September, 1995.

[DMK95]クリストル、D.M.、<>で入手可能な "提案HTTP状態-情報機構"、1995年9月。

[Netscape] "Persistent Client State -- HTTP Cookies", available at <>, undated.

日付のない<>で利用可能、 - [ネットスケープ] "HTTPクッキー永続的なクライアントの状態"。

[RFC2109] Kristol, D. and L. Montulli, "HTTP State Management Mechanism", RFC 2109, February 1997.

[RFC2109]クリストル、D.およびL. Montulli、 "HTTP状態管理機構"、RFC 2109、1997年2月。

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

[RFC2119]ブラドナーの、S.、 "要件レベルを示すためにRFCsにおける使用のためのキーワード"、BCP 14、RFC 2119、1997年3月。

[RFC2279] Yergeau, F., "UTF-8, a transformation format of Unicode and ISO-10646", RFC 2279, January 1998.

[RFC2279] Yergeau、F.、 "UTF-8、ユニコードの変換フォーマット及びISO-10646"、RFC 2279、1998年1月。

[RFC2396] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998.

[RFC2396]バーナーズ=リー、T.、フィールディング、R.、およびL. Masinter、 "統一資源識別子(URI):一般的な構文"、RFC 2396、1998年8月。

[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H. and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

[RFC2616]フィールディング、R.、ゲティス、J.、モーグル、J.、Frystyk、H.、およびT.バーナーズ - リー、 "ハイパーテキスト転送プロトコル - HTTP / 1.1"、RFC 2616、1999年6月。


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