Network Working Group B. Volz
Request for Comments: 3942 Cisco Systems, Inc.
Updates: 2132 November 2004
Category: Standards Track
Network Working Group B. Volz
Request for Comments: 3942 Cisco Systems, Inc.
Updates: 2132 November 2004
Category: Standards Track
Reclassifying Dynamic Host Configuration Protocol version 4 (DHCPv4) Options
重新分类动态主机配置协议版本4（DHCPv4）选项
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 (2004).
版权所有（C）互联网协会（2004年）。
Abstract
摘要
This document updates RFC 2132 to reclassify Dynamic Host Configuration Protocol version 4 (DHCPv4) option codes 128 to 223 (decimal) as publicly defined options to be managed by IANA in accordance with RFC 2939. This document directs IANA to make these option codes available for assignment as publicly defined DHCP options for future options.
本文档更新了RFC 2132，将动态主机配置协议版本4（DHCPv4）选项代码128至223（十进制）重新分类为IANA根据RFC 2939管理的公开定义选项。本文件指示IANA将这些选项代码作为公开定义的DHCP选项分配给未来的选项。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 2
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.1. Publicly Defined Options Range . . . . . . . . . . . . . 2
3.2. Site-Specific Options Range . . . . . . . . . . . . . . 3
4. Reclassifying Options . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 2
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.1. Publicly Defined Options Range . . . . . . . . . . . . . 2
3.2. Site-Specific Options Range . . . . . . . . . . . . . . 3
4. Reclassifying Options . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 7
The DHCPv4 [RFC2131] publicly defined options range, options 1 - 127, is nearly used up. Efforts such as [RFC3679] help extend the life of this space, but ultimately the space will be exhausted.
DHCPv4[RFC2131]公开定义的选项范围，选项1-127，几乎用完了。[RFC3679]等努力有助于延长该空间的寿命，但最终该空间将耗尽。
This document reclassifies much of the site-specific option range, which has not been widely used for its original intended purpose, to extend the publicly defined options space.
本文件重新分类了许多特定于现场的选项范围，这些选项未被广泛用于其原始预期目的，以扩展公开定义的选项空间。
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 DHCP option space (0 - 255) is divided into two ranges [RFC2132]:
DHCP选项空间（0-255）分为两个范围[RFC2132]：
1. 1 - 127 are publicly defined options, now allocated in accordance with [RFC2939].
1. 1-127是公开定义的期权，现在根据[RFC2939]进行分配。
2. 128 - 254 are site-specific options.
2. 128-254是特定于站点的选项。
Options 0 (pad) and 255 (end) are special and defined in [RFC2131].
选项0（pad）和255（end）是特殊的，并在[RFC2131]中定义。
The publicly defined options space (1 - 127) is nearly exhausted. Recent work [RFC3679] will buy more time, as several allocated but unused option codes have been reclaimed. A review could be made from time to time to determine whether there are other option codes that can be reclaimed.
公开定义的选项空间（1-127）几乎用尽了。最近的工作[RFC3679]将赢得更多的时间，因为已经回收了几个已分配但未使用的选项代码。可不时进行审查，以确定是否存在可回收的其他选项代码。
A longer-term solution to the eventual exhaustion of the publicly defined options space is desired. The DHC WG evaluated several solutions:
对于最终耗尽公开定义的期权空间，需要一个长期的解决方案。DHC工作组评估了几种解决方案：
1. Using options 126 and 127 to carry 16-bit options as originally proposed by Ralph Droms in late 1996. However, this significantly penalizes the first option assigned to this new space, as it requires implementing the 16-bit option support. Because of this, options 126 and 127 have been reclaimed [RFC3679].
1. 使用选项126和127携带Ralph Droms在1996年末最初提出的16位选项。但是，这会严重影响分配给这个新空间的第一个选项，因为它需要实现16位选项支持。因此，方案126和127已回收[RFC3679]。
2. Using a new magic cookie and 16-bit option code format. However, this proposal
2. 使用新的magic cookie和16位选项代码格式。然而，这项建议
* penalizes the first option assigned to this new space, as it requires significant changes to clients, servers, and relay agents,
* 惩罚分配给此新空间的第一个选项，因为它需要对客户端、服务器和中继代理进行重大更改，
* could adversely impact existing clients, servers, and relay agents that fail to properly check the magic cookie value,
* 可能对无法正确检查magic cookie值的现有客户端、服务器和中继代理产生不利影响，
* requires support of both message formats for the foreseeable future, and
* 在可预见的将来需要支持两种消息格式，以及
* requires clients to send multiple DHCPDISCOVER messages -- one for each magic cookie.
* 要求客户端发送多条DHCPDISCOVER消息——每个魔法cookie一条消息。
3. Reclassifying a portion of the site-specific option codes as publicly defined. The impact is minimal, as only those sites presently using options in the reclassified range need to renumber their options.
3. 根据公开定义，对部分现场特定选项代码进行重新分类。影响很小，因为只有目前使用重新分类范围内选项的站点需要重新编号其选项。
The site-specific option range is rather large (127 options in all) and little used. The original intent of the site-specific option range was to support local (to a site) configuration options, and it is difficult to believe a site would need 127 options for this purpose. Further, many DHCP client implementations do not provide a well documented means to request site-specific options from a server or to allow applications to extract the returned option values.
站点特定的选项范围相当大（总共127个选项），很少使用。站点特定选项范围的初衷是支持本地（到站点）配置选项，很难相信站点为此需要127个选项。此外，许多DHCP客户机实现没有提供一种记录良好的方法来从服务器请求特定于站点的选项或允许应用程序提取返回的选项值。
Some vendors have made use of site-specific option codes that violate the intent of the site-specific options, as the options are used to configure features of their products and thus are specific to many sites. This usage could potentially cause problems if a site that has been using the same site-specific option codes for other purposes deploys products from one of the vendors, or if two vendors pick the same site-specific options.
一些供应商使用了违反站点特定选项意图的站点特定选项代码，因为这些选项用于配置其产品的功能，因此特定于许多站点。如果出于其他目的使用相同站点特定选项代码的站点部署了其中一个供应商的产品，或者如果两个供应商选择了相同的站点特定选项，则此用法可能会导致问题。
The site-specific option codes 128 to 223 are hereby reclassified as publicly defined options. This leaves 31 site-specific options, 224 to 254.
现场特定选项代码128至223在此重新归类为公开定义的选项。这就剩下31个站点特定选项，224到254个。
To allow vendors that have made use of site-specific options within the reclassified range to publish their option usage and to request an official assignment of the option number to that usage, the following procedure will be used to reclassify these options:
为了允许在重新分类范围内使用现场特定选项的供应商公布其选项使用情况，并请求将选项编号正式分配给该使用情况，将使用以下程序对这些选项进行重新分类：
1. The reclassified options (128 to 223) will be placed in the "Unavailable" state by IANA. These options are not yet available for assignment to publicly defined options.
1. IANA将重新分类的选项（128至223）置于“不可用”状态。这些选项尚未分配给公开定义的选项。
2. Vendors that currently use one or more of the reclassified options have 6 months following this RFC's publication date to notify the DHC WG and IANA that they are using particular options numbers and agree to document that usage in an RFC. IANA will move these options from the "Unavailable" to "Tentatively Assigned" state.
2. 目前使用一个或多个重新分类选项的供应商在本RFC发布日期后有6个月的时间通知DHC WG和IANA他们正在使用特定选项编号，并同意在RFC中记录该使用情况。IANA将这些选项从“不可用”状态移动到“暂时分配”状态。
Vendors have 18 months from this RFC's publication date to start the documentation process by submitting an Internet-Draft.
从本RFC发布之日起，供应商有18个月的时间通过提交互联网草案开始文件编制过程。
NOTE: If multiple vendors of an option number come forward and can demonstrate that their usage is in reasonably wide use, none of the vendors will be allowed to keep the current option number, and they MUST go through the normal process of getting a publicly assigned option [RFC2939].
注：如果一个选项编号的多个供应商站出来，并且能够证明其使用范围相当广泛，则不允许任何供应商保留当前选项编号，并且他们必须通过获得公开分配选项的正常流程[RFC2939]。
3. Any options still classified as "Unavailable" 6 months after the RFC publication date will be moved to the "Unassigned" state by IANA. These options may then be assigned to any new publicly defined options in accordance with [RFC2939].
3. 在RFC发布日期后6个月，仍被归类为“不可用”的任何选项将由IANA移至“未分配”状态。然后，可根据[RFC2939]将这些期权分配给任何新的公开定义的期权。
4. For those options in the "Tentatively Assigned" state, vendors have 18 months following this RFC's publication date to submit an Internet-Draft documenting the option. The documented usage MUST be consistent with the existing usage. When the option usage is published as an RFC, IANA will move the option to the "Assigned" state.
4. 对于处于“暂定分配”状态的选项，供应商在本RFC发布日期后有18个月的时间提交一份记录该选项的互联网草案。记录的用途必须与现有用途一致。当选项用法发布为RFC时，IANA会将选项移动到“已分配”状态。
If no Internet-Draft is published within the 18 months or should one of these Internet-Drafts expire after the 18 months, IANA will move the option to the "Unassigned" state, and the option may then be assigned to any new publicly defined options in accordance with [RFC2939].
如果在18个月内未发布任何互联网草案，或者如果其中一份互联网草案在18个月后到期，IANA将把期权移至“未分配”状态，然后根据[RFC2939]将期权分配给任何新的公开定义的期权。
Sites presently using site-specific option codes within the reclassified range SHOULD take steps to renumber these options to values within the remaining range. If a site needs more than 31 site-specific options, the site must switch to using suboptions, as has been done for other options, such as the Relay Agent Information Option [RFC3046].
目前在重新分类范围内使用现场特定选项代码的现场应采取措施将这些选项重新编号为剩余范围内的值。如果站点需要31个以上特定于站点的选项，则站点必须切换到使用子选项，就像对其他选项（如中继代理信息选项[RFC3046]）所做的那样。
This document in and by itself provides no security, nor does it impact existing DCHP security as described in [RFC2131].
本文档本身不提供安全性，也不影响[RFC2131]中所述的现有DCHP安全性。
IANA is requested to
请IANA
1. expand the publicly defined DHCPv4 options space from 1 - 127 to 1 - 223. The new options (128 - 223) are to be listed as "Unavailable" and MUST NOT be assigned to any publicly defined options.
1. 将公开定义的DHCPv4选项空间从1-127扩展到1-223。新选项（128-223）将被列为“不可用”，不得分配给任何公开定义的选项。
2. receive notices from vendors that have been using one or more of the options in the 128-223 range that they are using the option and are willing to document that usage. IANA will list these options as "Tentatively Assigned".
2. 从使用128-223范围内一个或多个选项的供应商处收到通知，告知他们正在使用该选项，并愿意记录该使用情况。IANA将这些选项列为“暂定”。
3. change the listing of any options listed as "Unavailable" to "Available" 6 months from this RFC's publication date. These options may now be assigned in accordance with [RFC2939].
3. 自本RFC发布之日起6个月内，将“不可用”选项列表更改为“可用”。现在可根据[RFC2939]分配这些选项。
4. change the listing of any options listed as "Tentatively-Assigned" to "Unavailable" 18 months from this RFC's publication date and periodically thereafter as long as there is an option listed as "Tentatively-Assigned", if no un-expired Internet-Draft exists documenting the usage.
4. 自本RFC发布之日起18个月内，将列为“暂定分配”的任何选项的列表更改为“不可用”，并在此后定期更改，只要有列为“暂定分配”的选项，如果不存在记录使用情况的未过期互联网草案。
Many thanks to Ralph Droms and Ted Lemon for their valuable input and earlier work on the various alternatives.
非常感谢拉尔夫·德罗姆斯和特德·莱蒙的宝贵意见和早期对各种替代品的研究。
[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。
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997.
[RFC2131]Droms，R.，“动态主机配置协议”，RFC21311997年3月。
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997.
[RFC2132]Alexander，S.和R.Droms，“DHCP选项和BOOTP供应商扩展”，RFC 21321997年3月。
[RFC2939] Droms, R., "Procedures and IANA Guidelines for Definition of New DHCP Options and Message Types", BCP 43, RFC 2939, September 2000.
[RFC2939]Droms，R.，“新DHCP选项和消息类型定义的程序和IANA指南”，BCP 43，RFC 2939，2000年9月。
[RFC3046] Patrick, M., "DHCP Relay Agent Information Option", RFC 3046, January 2001.
[RFC3046]Patrick，M.，“DHCP中继代理信息选项”，RFC3046，2001年1月。
[RFC3679] Droms, R., "Unused Dynamic Host Configuration Protocol (DHCP) Option Codes", RFC 3679, January 2004.
[RFC3679]Droms，R.，“未使用的动态主机配置协议（DHCP）选项代码”，RFC 3679，2004年1月。
Author's Address
作者地址
Bernard Volz Cisco Systems, Inc. 1414 Massachusetts Ave. Boxborough, MA 01719 USA
伯纳德·沃兹思科系统公司，美国马萨诸塞州博克斯伯勒马萨诸塞大道1414号，邮编01719
Phone: +1 978 936 0382
EMail: volz@cisco.com
Phone: +1 978 936 0382
EMail: volz@cisco.com
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