Network Working Group D. Wing
Request for Comments: 2530 Cisco Systems
Category: Standards Track March 1999
Network Working Group D. Wing
Request for Comments: 2530 Cisco Systems
Category: Standards Track March 1999
Indicating Supported Media Features Using Extensions to DSN and MDN
使用DSN和MDN扩展指示支持的媒体功能
Status of this Memo
本备忘录的状况
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
版权公告
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
There is a need in Internet mail and Internet fax for a recipient to indicate the media features it supports so that messages can be generated by senders without exceeding the recipient's abilities.
在Internet邮件和Internet传真中，收件人需要指明其支持的媒体功能，以便发件人可以在不超出收件人能力的情况下生成邮件。
This memo describes a format for generating Message Disposition Notifications [RFC2298] and Delivery Status Notifications [RFC1894] which contain such information. This information can be used by senders to avoid exceeding the recipient's capabilities when sending subsequent messages.
本备忘录描述了生成包含此类信息的邮件处置通知[RFC2298]和传递状态通知[RFC1894]的格式。发件人可以使用此信息来避免在发送后续邮件时超出收件人的能力。
The extensions described in this document can be used in Message Disposition Notifications [RFC2298] or Delivery Status Notifications [RFC1894], as appropriate for the implementation.
本文档中描述的扩展可以在消息处置通知[RFC2298]或传递状态通知[RFC1894]中使用，具体取决于实现。
Note that both DSNs and MDNs have drawbacks: DSNs are not available between all senders and receivers, and MDNs require the receiver to disclose message disposition information (or, if using the "denied" disposition-type, the time the disposition notification was generated).
请注意，DSN和MDN都有缺点：DSN在所有发送方和接收方之间不可用，MDN要求接收方披露消息处置信息（或者，如果使用“拒绝”处置类型，则为生成处置通知的时间）。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照[RFC2119]中所述进行解释。
The following extension is available to both DSN [RFC1894] and MDN [RFC2298] messages.
以下扩展对DSN[RFC1894]和MDN[RFC2298]消息都可用。
For a DSN message, the following per-recipient fields are defined (section 2.3 of [RFC1894]). For an MDN message, the following extension fields are defined (section 3.1 of [RFC2298]). Using the language of [RFC2234]:
对于DSN消息，定义了以下每个收件人字段（RFC1894第2.3节）。对于MDN消息，定义了以下扩展字段（RFC2298第3.1节）。使用[RFC2234]的语言：
extension-field = media-features CRLF
extension-field = media-features CRLF
media-features = "Media-Accept-Features" ":"
media-feature-tags
media-feature-tags = <*text as defined below,
with LWSP wrapping>
media-features = "Media-Accept-Features" ":"
media-feature-tags
media-feature-tags = <*text as defined below,
with LWSP wrapping>
The <media-feature-tags> are defined in separate schema documents which MUST utilize the language described in [SYNTAX]. The schema MUST be registered following the registration requirements of [RFC2506].
<media feature tags>在单独的模式文档中定义，必须使用[SYNTAX]中描述的语言。必须按照[RFC2506]的注册要求注册架构。
The following examples assume there is a schema document which defines the tags shown.
以下示例假定存在一个模式文档，该文档定义了所示的标记。
Assuming there is a schema document which describes the tags paper-size and color, the following example is valid:
假设存在描述标签纸张大小和颜色的模式文档，则以下示例有效：
Media-Accept-Features: (& (paper-size=a4) (color=binary) )
Media-Accept-Features: (& (paper-size=a4) (color=binary) )
Assuming there is a schema document which describes the tags paper-size, color, and grey:
假设存在描述标签纸张大小、颜色和灰色的模式文档：
Media-Accept-Features: (& (| (paper-size=a4) (paper-size=letter) )
(| (& (color=grey) (dpi=200) (dpi-xyratio=200/100) )
(& (color=limited) (dpi=200) (dpi-xy=200/100) ) )
Media-Accept-Features: (& (| (paper-size=a4) (paper-size=letter) )
(| (& (color=grey) (dpi=200) (dpi-xyratio=200/100) )
(& (color=limited) (dpi=200) (dpi-xy=200/100) ) )
If the recipient's MTA determines that a message cannot be processed, the recipient's MTA is strongly encouraged to reject the message with a status code of 5.6.1 [RFC1893]. This status code may be returned
如果收件人的MTA确定无法处理邮件，强烈建议收件人的MTA拒绝状态代码为5.6.1[RFC1893]的邮件。可能会返回此状态代码
in response to the end-of-mail-data indicator if the MTA supports reporting of enhanced error codes [RFC2034], or after message reception by generating a delivery failure DSN ("bounce").
如果MTA支持报告增强的错误代码[RFC2034]，则响应邮件结束数据指示器，或者在收到邮件后，通过生成传递失败DSN（“跳出”）来响应。
Inaccurate media feature information could cause a denial of service, causing subsequent messages to be sent which the recipient is unable to process.
不准确的媒体功能信息可能导致拒绝服务，从而导致后续发送收件人无法处理的消息。
The media feature information could be inaccurate due to a malicious attack (spoofed DSN or MDN) or misconfiguration.
由于恶意攻击（伪造的DSN或MDN）或配置错误，媒体功能信息可能不准确。
The author thanks the members of the Internet Fax working group for assistance with this document, and especially Larry Masinter, Graham Klyne, and Ned Freed.
作者感谢互联网传真工作组成员对本文件的帮助，特别是拉里·马斯因特、格雷厄姆·克莱恩和内德·弗里德。
[RFC2506] Holtman, K., Mutz, A. and T. Hardie, "Media Feature Tag Registration Procedure", BCP 31, RFC 2506, March 1999.
[RFC2506]Holtman，K.，Mutz，A.和T.Hardie，“媒体功能标签注册程序”，BCP 31，RFC 2506，1999年3月。
[RFC1894] Moore, K. and G. Vaudreuil, "An Extensible Message Format for Delivery Status Notifications", RFC 1894, January 1996.
[RFC1894]Moore，K.和G.Vaudreuil，“交付状态通知的可扩展消息格式”，RFC 1894，1996年1月。
[RFC2034] Freed, N., "SMTP Service Extension for Returning Enhanced Error Codes", RFC 2034, October 1996.
[RFC2034]Freed，N.，“用于返回增强错误代码的SMTP服务扩展”，RFC 20341996年10月。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[RFC2234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997.
[RFC2234]Crocker，D.和P.Overell，“语法规范的扩充BNF:ABNF”，RFC 2234，1997年11月。
[RFC2298] Fajman, R., "An Extensible Message Format for Message Disposition Notifications", RFC 2298, March 1998.
[RFC2298]Fajman，R.，“用于消息处置通知的可扩展消息格式”，RFC2298，1998年3月。
[SYNTAX] Klyne, G., "A Syntax for Describing Media Feature Sets", RFC 2533, March 1999.
[语法]Klyne，G.“描述媒体功能集的语法”，RFC2531999年3月。
Dan Wing Cisco Systems, Inc. 101 Cooper Street Santa Cruz, CA 95060 USA
Dan Wing Cisco Systems，Inc.美国加利福尼亚州圣克鲁斯库珀街101号，邮编95060
Phone: +1 831 457 5200
Fax: +1 831 457 5208
EMail: dwing@cisco.com
Phone: +1 831 457 5200
Fax: +1 831 457 5208
EMail: dwing@cisco.com
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
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