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

本文件规定了互联网社区的互联网标准跟踪协议,并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态,请参考当前版本的“互联网官方协议标准”(STD 1)。本备忘录的分发不受限制。

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指出,当处理不包含任何点的主机名时,此机制在内部使用.local顶级域(TLD),并且如果实际注册了.local TLD,此机制可能无法以预期方式工作。



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.)


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

本文件反映了RFC 2109的实施经验,并将其淘汰。

1. 术语

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].


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.

术语request host和request URI是指客户端将分别作为http请求行的绝对URI(http_URL)的主机(而不是端口)和abs_路径部分发送给服务器的值。请注意,请求主机是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.


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


* their host name strings string-compare equal; or

* 它们的主机名字符串比较相等;或

* 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是HDN字符串,格式为NB,其中N是非空名称字符串,B的格式为.B',B'是HDN字符串。(因此,x.y.com域与.y.com匹配,但与y.com不匹配。)

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

* 如果

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

- H是主机的主机域名;和

- H has the form A.B; and

- H的形式为A.B;和

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

- A没有嵌入(即内部)点;和

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

- B至少有一个嵌入点,或者B是字符串“local”。那么H的范围是。

* Otherwise, the reach of H is H.

* 否则,H的可达范围为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.

对于表示路径的两个字符串P1和P2,如果P2是P1的前缀,则P1 path与P2匹配(包括P1和P2字符串比较相等的情况)。因此,字符串/tec/waldo路径与/tec匹配。

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
1.1 要求

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].

本文件中的关键词“可”、“必须”、“不得”、“可选”、“建议”、“要求”、“应”、“不应”、“应”、“不应”应按照RFC 2119[RFC2119]中所述进行解释。

2. 州和届会

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.


3. 描述

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
3.1 语法:一般

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.


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

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 源服务器角色

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 常规如果需要,源服务器将启动会话。为此,它向客户机Set-Cookie2返回一个额外的响应头。(详情见下文。)

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.

如果用户代理选择继续会话,它将向源服务器返回Cookie请求头(见下文)。源服务器可能会忽略它或使用它来确定会话的当前状态。它可以向客户端发回具有相同或不同信息的Set-Cookie2响应头,也可以根本不发送Set-Cookie2头。原始服务器通过向客户端发送一个Max Age=0的Set-Cookie2头来有效地结束会话。

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

3.2.2 Set-Cookie2语法Set-Cookie2响应头的语法为

   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
   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

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.


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.


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.


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]


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\u URL”可选。由于cookie可用于派生或存储用户的私人信息,因此CommentURL属性允许源服务器记录其打算如何使用cookie。用户可以检查URL标识的信息,以决定是否使用此cookie启动或继续会话。

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.


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.

最大年龄=可选值。Max Age属性的值是delta seconds,cookie的生存期(以秒为单位),是一个十进制非负整数。要正确处理缓存的cookie,客户端应根据HTTP/1.1规范[RFC2616]中的年龄计算规则计算cookie的年龄。当时间大于增量秒时,客户端应丢弃cookie。值为零表示应立即丢弃cookie。

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


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.


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.


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.


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 控制缓存源服务器必须了解可能缓存返回的资源和Set-Cookie2头的效果。缓存“公共”文档是可取的。例如,如果源服务器希望使用诸如“前门”页面之类的公共文档作为哨兵,以指示必须为其生成Set-Cookie2响应头的会话的开始,则该页面应存储在“预过期”的缓存中,以便源服务器将看到进一步的请求。“私有文档”,例如那些包含对会话严格私有的信息的文档,不应该缓存在共享缓存中。

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:


* To suppress caching of the Set-Cookie2 header:

* 要禁止缓存Set-Cookie2标头,请执行以下操作:

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


and one of the following:


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

* 要禁止在共享缓存中缓存私有文档,请执行以下操作:

Cache-control: private


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

* 要允许缓存文档并要求在将其返回到客户端之前对其进行验证,请执行以下操作:

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

* 要允许缓存文档,但要求代理缓存(而不是用户代理缓存)在将其返回到客户端之前对其进行验证,请执行以下操作:

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


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

* 要允许缓存文档并请求在将其返回到客户端之前对其进行验证(通过“预过期”方式),请执行以下操作:

Cache-control: max-age=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服务器必须在包含Set-Cookie2响应头的响应上发送Expires:old date(其中old date是过去很长的日期),除非它们确定(通过带外方式)响应链中没有HTTP/1.0代理。除了Expires:old-date指令外,HTTP/1.1服务器还可以发送允许HTTP/1.1代理缓存的其他缓存控制指令;缓存控制指令将覆盖HTTP/1.1代理的Expires:old日期。

3.3 User Agent Role
3.3 用户代理角色

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:

3.3.1 解释Set-Cookie2用户代理会单独跟踪通过Set-Cookie2响应头从每个源服务器(通过名称或IP地址和端口区分)到达的状态信息。用户代理必须忽略其属性无法识别的属性-值对。用户代理将这些默认值应用于缺少的可选属性:

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.)


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.

3.3.2 拒绝cookie为了防止可能的安全或隐私侵犯,用户代理会根据以下规则拒绝cookie。规则的目标是根据路径、域和端口属性的值以及请求URI、请求主机和请求端口,尝试限制cookie有效的服务器集。

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属性的值不是请求URI的前缀。

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

* 域属性的值不包含嵌入点,并且该值不是.local。

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

* 从请求主机派生的有效主机名与域属性不匹配。

* 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.

* 请求主机是一个HDN(不是IP地址),其格式为HD,其中D是Domain属性的值,H是包含一个或多个点的字符串。

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

* 端口属性有一个“端口列表”,请求端口不在列表中。



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

* 域的请求主机的Set-Cookie2将被拒绝,因为H是y.x并且包含一个点。

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

* 将接受来自请求主机的域的Set-Cookie2。

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

* 域为.com或域为.com的Set-Cookie2将始终被拒绝,因为没有嵌入的点。

* 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.

* 将接受Domain=ajax.com的Set-Cookie2,并且Domain的值将被取为,因为该值前面有一个点。

* 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.

* 如果向端口80或8000发出请求,则将接受端口为“808000”的Set-Cookie2,否则将被拒绝。

* 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.

* 由于请求主机的有效主机名为example.local,example.local域匹配.local,因此将接受来自请求主机example的Set-Cookie2。

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.

3.3.3 Cookie管理如果用户代理收到一个Set-Cookie2响应头,该响应头的名称与其以前存储的Cookie的名称相同,则新Cookie将在以下情况下取代旧Cookie:新旧域属性值比较相等,使用不区分大小写的字符串比较;并且,新旧路径属性值字符串比较相等(区分大小写)。但是,如果Set-Cookie2的Max Age值为零,则(旧的和新的)cookie将被丢弃。否则,cookie将一直存在(资源允许),直到先发生的情况发生为止,然后被丢弃:超过其最长使用寿命;或者,如果设置了Discard属性,则用户代理终止会话。

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;

* 用户代理接收包含CommentURL属性的cookie;

* 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;

* 用户代理的cookie检查界面被配置为在用户代理接受cookie之前向用户显示一个对话框;

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

* 该对话框允许用户在用户代理收到cookie时跟踪CommentURL链接;和

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

* 当用户遵循CommentURL链接时,源服务器(或其他服务器,通过返回内容中的其他链接)返回另一个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).

用户代理应该允许用户控制cookie销毁,但它们不能将cookie的生存期延长到由Discard和Max Age属性控制的生存期之外。一个不经常使用的cookie可以作为网络应用程序的“首选项文件”,用户可能希望保留它,即使它是最近使用最少的cookie。一个可能的实现是一个接口,该接口允许通过复选框永久存储cookie(或者,相反,允许立即销毁cookie)。

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

3.3.4 向源服务器发送Cookie当用户代理向源服务器发送请求时,如果用户代理存储了适用于该请求的Cookie,则该用户代理会根据

* the request-host and request-port;

* 请求主机和请求端口;

* the request-URI;

* 请求URI;

* the cookie's age.

* 饼干的年龄。

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 <"> ]
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 <"> ]

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

cookie version属性的值必须是相应Set-Cookie2响应头的version属性中的值。否则,cookie版本的值为0。路径的值

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.

1. 默认情况下(无端口属性),cookie可以发送到任何端口。

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.

2. 如果属性存在但没有值(例如端口),则必须仅将cookie发送到从中接收cookie的请求端口。

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.

3. 如果该属性具有端口列表,则只有当新请求端口是端口列表中列出的端口之一时,才能返回cookie。

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


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

3.3.5 确定理解的版本:Cookie2 Cookie2请求头有助于理解不同版本cookie规范的客户端和服务器之间的互操作。当客户端向源服务器发送一个或多个cookie时,如果这些cookie中至少有一个包含$Version属性,其值与客户端理解的版本不同,则客户端还必须发送Cookie2请求头,其语法为

cookie2 = "Cookie2:" cookie-version


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.

此处,cookie version的值是客户端理解的cookie规范的最高版本(当前为1)。客户端最多需要为每个请求发送一个这样的请求头。

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.

3.3.6 在无法验证的事务中发送cookie用户必须控制会话以确保隐私。(见下面的隐私部分。)为了简化实施并防止在存在充分保护措施的情况下增加复杂性,本文件对可验证交易和不可验证交易进行了区分。如果用户或用户指定的代理可以选择在事务中使用请求URI之前查看请求URI,则事务是可验证的。如果用户没有该选项,则事务无法验证。无法验证的事务通常在用户代理自动请求内联或嵌入式实体时出现,或者在它解析来自源服务器的重定向(3xx)响应时出现。通常,源事务(用户发起的事务)是可验证的,并且该事务可以直接或间接地诱导用户代理进行不可验证的事务。

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.


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.


3.4 How an Origin Server Interprets the Cookie Header
3.4 源服务器如何解释Cookie头

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
3.5 缓存代理角色

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:


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

* 如果可能,根据缓存有效性规则,接受来自缓存的请求。

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

* 在代理必须对其他服务器发出的任何请求中传递Cookie请求头。

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

* 将响应返回给客户端。包括任何Set-Cookie2响应头。

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

* 缓存接收到的响应,使其受常规头的控制,例如Expires,

Cache-control: no-cache



Cache-control: private


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

* 缓存Set-Cookie2,受常用头的控制,

Cache-control: no-cache="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. 例子
4.1 Example 1
4.1 例1

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


1. User Agent -> Server

1. 用户代理->服务器

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

POST/acme/login HTTP/1.1[表单数据]

User identifies self via a form.


2. Server -> User Agent

2. 服务器->用户代理

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

Cookie reflects user's identity.


3. User Agent -> Server

3. 用户代理->服务器

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

User selects an item for "shopping basket".


4. Server -> User Agent

4. 服务器->用户代理

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

Shopping basket contains an item.


5. User Agent -> Server

5. 用户代理->服务器

        POST /acme/shipping HTTP/1.1
        Cookie: $Version="1";
                Customer="WILE_E_COYOTE"; $Path="/acme";
                Part_Number="Rocket_Launcher_0001"; $Path="/acme"
        [form data]
        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. 服务器->用户代理

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

New cookie reflects shipping method.


7. User Agent -> Server

7. 用户代理->服务器

        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]
        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. 服务器->用户代理

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.

用户代理在源服务器上发出一系列请求,每次请求之后它都会收到一个新的cookie。所有cookie都具有相同的路径属性和(默认)域。因为请求uri是all path match/acme,即每个cookie的path属性,所以每个请求都包含迄今为止收到的所有cookie。

4.2 Example 2
4.2 例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";
   Set-Cookie2: Part_Number="Rocket_Launcher_0001"; Version="1";


   Set-Cookie2: Part_Number="Riding_Rocket_0023"; Version="1";
   Set-Cookie2: Part_Number="Riding_Rocket_0023"; Version="1";

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


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


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:


   Cookie: $Version="1"; Part_Number="Rocket_Launcher_0001";
   Cookie: $Version="1"; Part_Number="Rocket_Launcher_0001";

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.


5. 实施考虑

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


5.1 Set-Cookie2 Content
5.1 Set-Cookie2内容

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;

1. 在服务器端保持真实状态;

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

2. 当用户代理终止会话(例如退出)时,如何以及何时对数据库项进行垃圾收集。

5.2 Stateless Pages
5.2 无状态页面

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
5.3 实施限制

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

* 至少300块饼干

* 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)

* 每个cookie至少4096字节(由Set-Cookie2头的语法描述中组成cookie非终端的字符测量,并在Set-Cookie2头中接收)

* at least 20 cookies per unique host or domain name

* 每个唯一主机或域名至少20个cookie

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.

5.3.1 拒绝服务攻击用户代理可以选择对从给定主机或域名存储的cookie数量或cookie信息的大小设置上限。否则,恶意服务器可能试图在连续响应时向用户代理发送大量cookie或大型cookie,这将强制用户代理从其他服务器接收到cookie。但是,仍应支持上述规定的最小值。

6. 隐私

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
6.1 用户代理控制

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


* to completely disable the sending and saving of cookies.

* 完全禁用Cookie的发送和保存。

* to determine whether a stateful session is in progress.

* 确定有状态会话是否正在进行。

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

* 根据cookie的域属性控制cookie的保存。

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.

* 要在用户代理将要向源服务器发送cookie时通知用户,请提供不开始会话的选项。

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

* 显示有状态会话正在进行的可视指示。

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

* 让用户决定在用户结束窗口或用户代理会话时应保存哪些cookie(如果有)。

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

* 允许用户随时检查和删除cookie的内容。

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.)


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
6.2 源服务器角色

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.


6.3 Clear Text
6.3 明文

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.

1. 任何通过它们传递的敏感信息都会暴露给入侵者。

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

2. 恶意中介可能会在头文件沿任意方向移动时改变头文件,从而导致不可预知的结果。

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. 安全考虑
7.1 Protocol Design
7.1 协议设计

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.


7.2 Cookie Spoofing
7.2 曲奇欺骗

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. 用户代理向Victor.cracker.edu发出请求,返回cookie会话\u id=“1234”,并设置默认域。

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

2. 用户代理向spoof.cracker.edu发出请求,通过Domain=“”返回cookie会话id=“1111”。

3. User agent makes request to again, and passes

3. 用户代理再次向Victor.cracker.edu发出请求,并通过

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

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.


7.3 Unexpected Cookie Sharing
7.3 意外的Cookie共享

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
7.4 帐户信息的Cookies

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.


8. 其他类似建议

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].


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.

Brian Behlendorf提出了一个会话ID头,该头由用户代理启动,可由源服务器用于跟踪“点击轨迹”。但是,它不会携带任何源服务器定义的状态。Phillip Hallam Baker为类似目的提出了另一种客户端定义的会话ID机制。

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. 历史的
9.1 Compatibility with Existing Implementations
9.1 与现有实现的兼容性

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.


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"


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 缓存与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.

一些缓存,例如符合HTTP/1.0的缓存,将不可避免地缓存Set-Cookie2和Set-Cookie头,因为在HTTP/1.1之前没有抑制头缓存的机制。这种缓存会导致安全问题。原始服务器与Set-Cookie2和Set-Cookie头一起传输的文档通常是不可缓存的,或者是“预过期的”。只要缓存遵循不缓存文档的指示(过期后:<a date in the pass>或Pragma:no cache(HTTP/1.0)或cache control:no cache(HTTP/1.1)),不可缓存的文档就不会出现问题。但是,预过期的文档可能存储在缓存中。它们要求对每个新请求进行验证(有条件的GET),但一些缓存操作员放松了缓存规则,有时在未首先验证过期文档的情况下提供过期文档。这些因素的组合可能导致一个用户的cookie稍后被发送给另一个用户。Set-Cookie2和Set-Cookie头存储在缓存中,尽管文档已过时(过期),缓存仍会返回文档以响应稍后的请求,包括缓存头。

10. 致谢

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.

本文件真正代表了IETF HTTP工作组的集体努力,特别是以下人员,以及作者:Roy Fielding、Yaron Goland、Marc Hedlund、Ted Hardie、Koen Holtman、Shel Kaphan、Rohit Khare、Foteos Macrides、David W.Morris。

11. 作者地址

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

David M.Kristol Bell实验室,朗讯科技有限公司山路600号,新泽西州默里山2A-333室,邮编:07974

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


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

Lou Montulli,Inc.2037年加利福尼亚州山景城着陆博士94301

12. 参考资料

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

[DMK95]Kristol,D.M.,“提议的HTTP状态信息机制”,可在< info.html>,1995年9月。

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

[Netscape]“持久性客户端状态--HTTP Cookies”,可在<>,未注明日期。

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


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

[RFC2119]Bradner,S.,“RFC中用于表示需求水平的关键词”,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,Unicode和ISO-10646的转换格式”,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]Berners Lee,T.,Fielding,R.和L.Masinter,“统一资源标识符(URI):通用语法”,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]Fielding,R.,Gettys,J.,Mogul,J.,Frystyk,H.和T.Berners-Lee,“超文本传输协议——HTTP/1.1”,RFC 2616,1999年6月。

13. Full Copyright Statement
13. 完整版权声明

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


This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.


The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.






Funding for the RFC Editor function is currently provided by the Internet Society.