Internet Engineering Task Force (IETF)                        P. Hoffman
Request for Comments: 8499                                         ICANN
BCP: 219                                                     A. Sullivan
Obsoletes: 7719
Updates: 2308                                                K. Fujiwara
Category: Best Current Practice                                     JPRS
ISSN: 2070-1721                                             January 2019
Internet Engineering Task Force (IETF)                        P. Hoffman
Request for Comments: 8499                                         ICANN
BCP: 219                                                     A. Sullivan
Obsoletes: 7719
Updates: 2308                                                K. Fujiwara
Category: Best Current Practice                                     JPRS
ISSN: 2070-1721                                             January 2019

DNS Terminology




The Domain Name System (DNS) is defined in literally dozens of different RFCs. The terminology used by implementers and developers of DNS protocols, and by operators of DNS systems, has sometimes changed in the decades since the DNS was first defined. This document gives current definitions for many of the terms used in the DNS in a single document.


This document obsoletes RFC 7719 and updates RFC 2308.

本文件淘汰RFC 7719并更新RFC 2308。

Status of This Memo


This memo documents an Internet Best Current Practice.


This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on BCPs is available in Section 2 of RFC 7841.

本文件是互联网工程任务组(IETF)的产品。它代表了IETF社区的共识。它已经接受了公众审查,并已被互联网工程指导小组(IESG)批准出版。有关BCP的更多信息,请参见RFC 7841第2节。

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at


Copyright Notice


Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.

版权(c)2019 IETF信托基金和被确定为文件作者的人员。版权所有。

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents ( in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(自本文件出版之日起生效。请仔细阅读这些文件,因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本,并提供简化BSD许可证中所述的无担保。

Table of Contents


   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Names . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  DNS Response Codes  . . . . . . . . . . . . . . . . . . . . .  10
   4.  DNS Transactions  . . . . . . . . . . . . . . . . . . . . . .  11
   5.  Resource Records  . . . . . . . . . . . . . . . . . . . . . .  14
   6.  DNS Servers and Clients . . . . . . . . . . . . . . . . . . .  16
   7.  Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
   8.  Wildcards . . . . . . . . . . . . . . . . . . . . . . . . . .  27
   9.  Registration Model  . . . . . . . . . . . . . . . . . . . . .  28
   10. General DNSSEC  . . . . . . . . . . . . . . . . . . . . . . .  30
   11. DNSSEC States . . . . . . . . . . . . . . . . . . . . . . . .  34
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  36
   13. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  36
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  36
     14.1.  Normative References . . . . . . . . . . . . . . . . . .  36
     14.2.  Informative References . . . . . . . . . . . . . . . . .  39
   Appendix A.  Definitions Updated by This Document . . . . . . . .  44
   Appendix B.  Definitions First Defined in This Document . . . . .  44
   Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  50
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  50
   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Names . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  DNS Response Codes  . . . . . . . . . . . . . . . . . . . . .  10
   4.  DNS Transactions  . . . . . . . . . . . . . . . . . . . . . .  11
   5.  Resource Records  . . . . . . . . . . . . . . . . . . . . . .  14
   6.  DNS Servers and Clients . . . . . . . . . . . . . . . . . . .  16
   7.  Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
   8.  Wildcards . . . . . . . . . . . . . . . . . . . . . . . . . .  27
   9.  Registration Model  . . . . . . . . . . . . . . . . . . . . .  28
   10. General DNSSEC  . . . . . . . . . . . . . . . . . . . . . . .  30
   11. DNSSEC States . . . . . . . . . . . . . . . . . . . . . . . .  34
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  36
   13. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  36
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  36
     14.1.  Normative References . . . . . . . . . . . . . . . . . .  36
     14.2.  Informative References . . . . . . . . . . . . . . . . .  39
   Appendix A.  Definitions Updated by This Document . . . . . . . .  44
   Appendix B.  Definitions First Defined in This Document . . . . .  44
   Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  50
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  50
1. Introduction
1. 介绍

The Domain Name System (DNS) is a simple query-response protocol whose messages in both directions have the same format. (Section 2 gives a definition of "public DNS", which is often what people mean when they say "the DNS".) The protocol and message format are defined in [RFC1034] and [RFC1035]. These RFCs defined some terms, and later documents defined others. Some of the terms from [RFC1034] and [RFC1035] have somewhat different meanings now than they did in 1987.


This document contains a collection of a wide variety of DNS-related terms, organized loosely by topic. Some of them have been precisely defined in earlier RFCs, some have been loosely defined in earlier RFCs, and some are not defined in an earlier RFC at all.


Other organizations sometimes define DNS-related terms their own way. For example, the WHATWG defines "domain" at <>. The Root Server System Advisory Committee (RSSAC) has a good lexicon [RSSAC026].

其他组织有时以自己的方式定义DNS相关术语。例如,WHATWG在<>. 根服务器系统咨询委员会(RSSAC)有一个很好的词典[RSSAC026]。

Most of the definitions listed here represent the consensus definition of the DNS community -- both protocol developers and operators. Some of the definitions differ from earlier RFCs, and those differences are noted. In this document, where the consensus definition is the same as the one in an RFC, that RFC is quoted. Where the consensus definition has changed somewhat, the RFC is mentioned but the new stand-alone definition is given. See Appendix A for a list of the definitions that this document updates.


It is important to note that, during the development of this document, it became clear that some DNS-related terms are interpreted quite differently by different DNS experts. Further, some terms that are defined in early DNS RFCs now have definitions that are generally agreed to, but that are different from the original definitions. Therefore, this document is a substantial revision to [RFC7719].

需要注意的是,在本文档的开发过程中,不同的DNS专家对某些DNS相关术语的解释明显不同。此外,早期DNS RFC中定义的一些术语现在具有普遍认可的定义,但与原始定义不同。因此,本文件是对[RFC7719]的实质性修订。

Note that there is no single consistent definition of "the DNS". It can be considered to be some combination of the following: a commonly used naming scheme for objects on the Internet; a distributed database representing the names and certain properties of these objects; an architecture providing distributed maintenance, resilience, and loose coherency for this database; and a simple query-response protocol (as mentioned below) implementing this architecture. Section 2 defines "global DNS" and "private DNS" as a way to deal with these differing definitions.


Capitalization in DNS terms is often inconsistent among RFCs and various DNS practitioners. The capitalization used in this document is a best guess at current practices, and is not meant to indicate that other capitalization styles are wrong or archaic. In some cases, multiple styles of capitalization are used for the same term due to quoting from different RFCs.


Readers should note that the terms in this document are grouped by topic. Someone who is not already familiar with the DNS probably cannot learn about the DNS from scratch by reading this document from front to back. Instead, skipping around may be the only way to get enough context to understand some of the definitions. This document has an index that might be useful for readers who are attempting to learn the DNS by reading this document.


2. Names
2. 名字

Naming system: A naming system associates names with data. Naming systems have many significant facets that help differentiate them from each other. Some commonly identified facets include:


* Composition of names

* 姓名的构成

* Format of names

* 姓名格式

* Administration of names

* 姓名管理

* Types of data that can be associated with names

* 可以与名称关联的数据类型

* Types of metadata for names

* 名称的元数据类型

* Protocol for getting data from a name

* 从名称获取数据的协议

* Context for resolving a name

* 用于解析名称的上下文

Note that this list is a small subset of facets that people have identified over time for naming systems, and the IETF has yet to agree on a good set of facets that can be used to compare naming systems. For example, other facets might include "protocol to update data in a name", "privacy of names", and "privacy of data associated with names", but those are not as well defined as the ones listed above. The list here is chosen because it helps describe the DNS and naming systems similar to the DNS.


Domain name: An ordered list of one or more labels.


Note that this is a definition independent of the DNS RFCs ([RFC1034] and [RFC1035]), and the definition here also applies to systems other than the DNS. [RFC1034] defines the "domain name space" using mathematical trees and their nodes in graph theory, and that definition has the same practical result as the definition here. Any path of a directed acyclic graph can be represented by a domain name consisting of the labels of its nodes, ordered by decreasing distance from the root(s) (which is the normal convention within the DNS, including this document). A domain name whose last label identifies a root of the graph is fully qualified; other domain names whose labels form a strict prefix of a fully-qualified domain name are relative to its first omitted node.

请注意,这是一个独立于DNS RFC([RFC1034]和[RFC1035])的定义,此处的定义也适用于DNS以外的系统。[RFC1034]使用图论中的数学树及其节点定义了“域名空间”,该定义与此处的定义具有相同的实际结果。有向无环图的任何路径都可以由一个域名表示,该域名由其节点的标签组成,按与根的距离递减的顺序排列(这是DNS中的常规约定,包括本文档)。最后一个标签标识图形根的域名是完全限定的;标签构成完全限定域名的严格前缀的其他域名相对于其第一个省略的节点。

Also note that different IETF and non-IETF documents have used the term "domain name" in many different ways. It is common for earlier documents to use "domain name" to mean "names that match the syntax in [RFC1035]", but possibly with additional rules such as "and are, or will be, resolvable in the global DNS" or "but only using the presentation format".


Label: An ordered list of zero or more octets that makes up a portion of a domain name. Using graph theory, a label identifies one node in a portion of the graph of all possible domain names.


Global DNS: Using the short set of facets listed in "Naming system", the global DNS can be defined as follows. Most of the rules here come from [RFC1034] and [RFC1035], although the term "global DNS" has not been defined before now.


Composition of names: A name in the global DNS has one or more labels. The length of each label is between 0 and 63 octets inclusive. In a fully-qualified domain name, the last label in the ordered list is 0 octets long; it is the only label whose length may be 0 octets, and it is called the "root" or "root label". A domain name in the global DNS has a maximum total length of 255 octets in the wire format; the root represents one octet for this calculation. (Multicast DNS [RFC6762] allows names up to 255 bytes plus a terminating zero byte based on a different interpretation of RFC 1035 and what is included in the 255 octets.)

名称组合:全局DNS中的名称具有一个或多个标签。每个标签的长度介于0到63个八位字节(含)之间。在完全限定域名中,有序列表中的最后一个标签长度为0个八位字节;它是唯一长度为0个八位字节的标签,称为“根”或“根标签”。全局DNS中的域名在有线格式中的最大总长度为255个八位字节;根表示此计算的一个八位字节。(多播DNS[RFC6762]允许最多255个字节的名称加上一个终止的零字节,这基于对RFC 1035的不同解释以及255个八位字节中包含的内容。)

Format of names: Names in the global DNS are domain names. There are three formats: wire format, presentation format, and common display.


The basic wire format for names in the global DNS is a list of labels ordered by decreasing distance from the root, with the root label last. Each label is preceded by a length octet. [RFC1035] also defines a compression scheme that modifies this format.


The presentation format for names in the global DNS is a list of labels ordered by decreasing distance from the root, encoded as ASCII, with a "." character between each label. In presentation format, a fully-qualified domain name includes the root label and the associated separator dot. For example, in presentation format, a fully-qualified domain name with two non-root labels is always shown as "example.tld." instead of "example.tld". [RFC1035] defines a method for showing octets that do not display in ASCII.


The common display format is used in applications and free text. It is the same as the presentation format, but showing the root label and the "." before it is optional and is rarely done. For example, in common display format, a fully-qualified domain name with two non-root labels is usually shown as "example.tld" instead of "example.tld.". Names in the common display format are normally written such that the directionality of the writing system presents labels by decreasing distance from the root (so, in both English and the C programming language the root or Top-Level Domain (TLD) label in the ordered list is rightmost; but in Arabic, it may be leftmost, depending on local conventions).


Administration of names: Administration is specified by delegation (see the definition of "delegation" in Section 7). Policies for administration of the root zone in the global DNS are determined by the names operational community, which convenes itself in the Internet Corporation for Assigned Names and Numbers (ICANN). The names operational community selects the IANA Functions Operator for the global DNS root zone. At the time of writing, that operator is Public Technical Identifiers (PTI). (See <> for more information about PTI operating the IANA Functions.) The name servers that serve the root zone are provided by independent root operators. Other zones in the global DNS have their own policies for administration.

名称管理:管理由授权指定(见第7节“授权”的定义)。全球DNS中根区域的管理策略由名称运营社区决定,该社区成立于互联网名称和号码分配公司(ICANN)。names operational community为全局DNS根区域选择IANA Functions操作符。在撰写本文时,该运营商是公共技术标识符(PTI)。(见<>有关PTI操作IANA功能的更多信息。)为根区域提供服务的名称服务器由独立的根操作员提供。全局DNS中的其他区域有自己的管理策略。

Types of data that can be associated with names: A name can have zero or more resource records associated with it. There are numerous types of resource records with unique data structures defined in many different RFCs and in the IANA registry at [IANA_Resource_Registry].


Types of metadata for names: Any name that is published in the DNS appears as a set of resource records (see the definition of "RRset" in Section 5). Some names do not, themselves, have data associated with them in the DNS, but they "appear" in the DNS anyway because they form part of a longer name that does have data associated with it (see the definition of "empty non-terminals" in Section 7).


Protocol for getting data from a name: The protocol described in [RFC1035].


Context for resolving a name: The global DNS root zone distributed by PTI.


Private DNS: Names that use the protocol described in [RFC1035] but that do not rely on the global DNS root zone or names that are otherwise not generally available on the Internet but are using the protocol described in [RFC1035]. A system can use both the global DNS and one or more private DNS systems; for example, see "Split DNS" in Section 6.


Note that domain names that do not appear in the DNS, and that are intended never to be looked up using the DNS protocol, are not part of the global DNS or a private DNS even though they are domain names.


Multicast DNS (mDNS): "Multicast DNS (mDNS) provides the ability to perform DNS-like operations on the local link in the absence of any conventional Unicast DNS server. In addition, Multicast DNS designates a portion of the DNS namespace to be free for local use, without the need to pay any annual fee, and without the need to set up delegations or otherwise configure a conventional DNS server to answer for those names." (Quoted from [RFC6762], Abstract) Although it uses a compatible wire format, mDNS is, strictly speaking, a different protocol than DNS. Also, where the above quote says "a portion of the DNS namespace", it would be clearer to say "a portion of the domain name space". The names in mDNS are not intended to be looked up in the DNS.


Locally served DNS zone: A locally served DNS zone is a special case of private DNS. Names are resolved using the DNS protocol in a local context. [RFC6303] defines subdomains of IN-ADDR.ARPA that are locally served zones. Resolution of names through locally served zones may result in ambiguous results. For example, the same name may resolve to different results in different locally served DNS zone contexts. The context for a locally served DNS zone may be explicit, such as those that are listed in [RFC6303] and [RFC7793], or implicit, such as those defined by local DNS administration and not known to the resolution client.


Fully-Qualified Domain Name (FQDN): This is often just a clear way of saying the same thing as "domain name of a node", as outlined above. However, the term is ambiguous. Strictly speaking, a fully-qualified domain name would include every label, including the zero-length label of the root: such a name would be written "" (note the terminating dot). But, because every name eventually shares the common root, names are often written relative to the root (such as "") and are still called "fully qualified". This term first appeared in [RFC819]. In this document, names are often written relative to the root.


The need for the term "fully-qualified domain name" comes from the existence of partially qualified domain names, which are names where one or more of the last labels in the ordered list are omitted (for example, a domain name of "www" relative to "" identifies ""). Such relative names are understood only by context.


Host name: This term and its equivalent, "hostname", have been widely used but are not defined in [RFC1034], [RFC1035], [RFC1123], or [RFC2181]. The DNS was originally deployed into the Host Tables environment as outlined in [RFC952], and it is likely that the term followed informally from the definition there. Over time, the definition seems to have shifted. "Host name" is often meant to be a domain name that follows the rules in Section 3.5 of [RFC1034], which is also called the "preferred name syntax". (In that syntax, every character in each label is a letter, a digit, or a hyphen). Note that any label in a domain name can contain any octet value; hostnames are generally considered to be domain names where every label follows the rules in the "preferred name syntax", with the amendment that labels can start with ASCII digits (this amendment comes from Section 2.1 of [RFC1123]).


People also sometimes use the term "hostname" to refer to just the first label of an FQDN, such as "printer" in "". (Sometimes this is formalized in configuration in operating systems.) In addition, people


sometimes use this term to describe any name that refers to a machine, and those might include labels that do not conform to the "preferred name syntax".


Top-Level Domain (TLD): A Top-Level Domain is a zone that is one layer below the root, such as "com" or "jp". There is nothing special, from the point of view of the DNS, about TLDs. Most of them are also delegation-centric zones (defined in Section 7), and there are significant policy issues around their operation. TLDs are often divided into sub-groups such as Country Code Top-Level Domains (ccTLDs), Generic Top-Level Domains (gTLDs), and others; the division is a matter of policy and beyond the scope of this document.


Internationalized Domain Name (IDN): The Internationalized Domain Names for Applications (IDNA) protocol is the standard mechanism for handling domain names with non-ASCII characters in applications in the DNS. The current standard at the time of this writing, normally called "IDNA2008", is defined in [RFC5890], [RFC5891], [RFC5892], [RFC5893], and [RFC5894]. These documents define many IDN-specific terms such as "LDH label", "A-label", and "U-label". [RFC6365] defines more terms that relate to internationalization (some of which relate to IDNs); [RFC6055] has a much more extensive discussion of IDNs, including some new terminology.


Subdomain: "A domain is a subdomain of another domain if it is contained within that domain. This relationship can be tested by seeing if the subdomain's name ends with the containing domain's name." (Quoted from [RFC1034], Section 3.1) For example, in the host name "", both "" and "" are subdomains of "". Note that the comparisons here are done on whole labels; that is, "" is not a subdomain of "".


Alias: The owner of a CNAME resource record, or a subdomain of the owner of a DNAME resource record (DNAME records are defined in [RFC6672]). See also "canonical name".


Canonical name: A CNAME resource record "identifies its owner name as an alias, and specifies the corresponding canonical name in the RDATA section of the RR." (Quoted from [RFC1034], Section 3.6.2) This usage of the word "canonical" is related to the mathematical concept of "canonical form".


CNAME: "It has been traditional to refer to the [owner] of a CNAME record as 'a CNAME'. This is unfortunate, as 'CNAME' is an abbreviation of 'canonical name', and the [owner] of a CNAME record is most certainly not a canonical name." (Quoted from [RFC2181], Section 10.1.1. The quoted text has been changed from "label" to "owner".)


3. DNS Response Codes
3. DNS响应码

Some of the response codes (RCODEs) that are defined in [RFC1035] have acquired their own shorthand names. All of the RCODEs are listed at [IANA_Resource_Registry], although that list uses mixed-case capitalization, while most documents use all caps. Some of the common names for values defined in [RFC1035] are described in this section. This section also includes an additional RCODE and a general definition. The official list of all RCODEs is in the IANA registry.


NOERROR: This RCODE appears as "No error condition" in Section 4.1.1 of [RFC1035].


FORMERR: This RCODE appears as "Format error - The name server was unable to interpret the query" in Section 4.1.1 of [RFC1035].


SERVFAIL: This RCODE appears as "Server failure - The name server was unable to process this query due to a problem with the name server" in Section 4.1.1 of [RFC1035].


NXDOMAIN: This RCODE appears as "Name Error [...] this code signifies that the domain name referenced in the query does not exist." in Section 4.1.1 of [RFC1035]. [RFC2308] established NXDOMAIN as a synonym for Name Error.


NOTIMP: This RCODE appears as "Not Implemented - The name server does not support the requested kind of query" in Section 4.1.1 of [RFC1035].


REFUSED: This RCODE appears as "Refused - The name server refuses to perform the specified operation for policy reasons. For example, a name server may not wish to provide the information to the particular requester, or a name server may not wish to perform a particular operation (e.g., zone transfer) for particular data." in Section 4.1.1 of [RFC1035].


NODATA: "A pseudo RCODE which indicates that the name is valid, for the given class, but [there] are no records of the given type. A NODATA response has to be inferred from the answer." (Quoted from [RFC2308], Section 1) "NODATA is indicated by an answer with the


RCODE set to NOERROR and no relevant answers in the Answer section. The authority section will contain an SOA record, or there will be no NS records there." (Quoted from [RFC2308], Section 2.2) Note that referrals have a similar format to NODATA replies; [RFC2308] explains how to distinguish them.


The term "NXRRSET" is sometimes used as a synonym for NODATA. However, this is a mistake, given that NXRRSET is a specific error code defined in [RFC2136].


Negative response: A response that indicates that a particular RRset does not exist or whose RCODE indicates that the nameserver cannot answer. Sections 2 and 7 of [RFC2308] describe the types of negative responses in detail.


4. DNS Transactions
4. DNS事务

The header of a DNS message is its first 12 octets. Many of the fields and flags in the diagrams in Sections 4.1.1 through 4.1.3 of [RFC1035] are referred to by their names in each diagram. For example, the response codes are called "RCODEs", the data for a record is called the "RDATA", and the authoritative answer bit is often called "the AA flag" or "the AA bit".


Class: A class "identifies a protocol family or instance of a protocol". (Quoted from [RFC1034], Section 3.6) "The DNS tags all data with a class as well as the type, so that we can allow parallel use of different formats for data of type address." (Quoted from [RFC1034], Section 2.2) In practice, the class for nearly every query is "IN" (the Internet). There are some queries for "CH" (the Chaos class), but they are usually for the purposes of information about the server itself rather than for a different type of address.


QNAME: The most commonly used rough definition is that the QNAME is a field in the Question section of a query. "A standard query specifies a target domain name (QNAME), query type (QTYPE), and query class (QCLASS) and asks for RRs which match." (Quoted from [RFC1034], Section 3.7.1) Strictly speaking, the definition comes from [RFC1035], Section 4.1.2, where the QNAME is defined in respect of the Question section. This definition appears to be applied consistently: the discussion of inverse queries in Section 6.4.1 refers to the "owner name of the query RR and its TTL", because inverse queries populate the Answer section and leave the Question section empty. (Inverse queries are deprecated in [RFC3425]; thus, relevant definitions do not appear in this document.)


However, [RFC2308] has an alternate definition that puts the QNAME in the answer (or series of answers) instead of the query. It defines QNAME as "...the name in the query section of an answer, or where this resolves to a CNAME, or CNAME chain, the data field of the last CNAME. The last CNAME in this sense is that which contains a value which does not resolve to another CNAME." This definition has a certain internal logic, because of the way CNAME substitution works and the definition of CNAME. If a name server does not find an RRset that matches a query, but does find the same name in the same class with a CNAME record, then the name server "includes the CNAME record in the response and restarts the query at the domain name specified in the data field of the CNAME record." (Quoted from [RFC1034], Section 3.6.2) This is made explicit in the resolution algorithm outlined in Section 4.3.2 of [RFC1034], which says to "change QNAME to the canonical name in the CNAME RR, and go back to step 1" in the case of a CNAME RR. Since a CNAME record explicitly declares that the owner name is canonically named what is in the RDATA, then there is a way to view the new name (i.e., the name that was in the RDATA of the CNAME RR) as also being the QNAME.

但是,[RFC2308]有一个替代定义,将QNAME放在答案(或一系列答案)中,而不是查询中。它将QNAME定义为“…答案查询部分中的名称,或解析为CNAME或CNAME链的名称,最后一个CNAME的数据字段。从这个意义上讲,最后一个CNAME包含的值不会解析为另一个CNAME。”此定义具有一定的内部逻辑,因为CNAME替换的工作方式和CNAME的定义。如果名称服务器未找到与查询匹配的RRset,但在具有CNAME记录的同一类中找到了相同的名称,则名称服务器“在响应中包括CNAME记录,并在CNAME记录的数据字段中指定的域名处重新启动查询。”(引自[RFC1034],第3.6.2节)[RFC1034]第4.3.2节中概述的解析算法明确了这一点,该算法表示在CNAME RR中“将QNAME更改为规范名称,并在CNAME RR中返回到步骤1”。由于CNAME记录明确声明所有者名称按规范命名为RDATA中的名称,因此有一种方法可以将新名称(即CNAME RR的RDATA中的名称)视为QNAME。

However, this creates a kind of confusion because the response to a query that results in CNAME processing contains in the echoed Question section one QNAME (the name in the original query) and a second QNAME that is in the data field of the last CNAME. The confusion comes from the iterative/recursive mode of resolution, which finally returns an answer that need not actually have the same owner name as the QNAME contained in the original query.


To address this potential confusion, it is helpful to distinguish between three meanings:


* QNAME (original): The name actually sent in the Question section in the original query, which is always echoed in the (final) reply in the Question section when the QR bit is set to 1.

* QNAME(原件):在原始查询的问题部分实际发送的名称,当QR位设置为1时,该名称始终在问题部分的(最终)答复中回显。

* QNAME (effective): A name actually resolved, which is either the name originally queried or a name received in a CNAME chain response.

* QNAME(有效):实际解析的名称,可以是最初查询的名称,也可以是CNAME链响应中接收到的名称。

* QNAME (final): The name actually resolved, which is either the name actually queried or else the last name in a CNAME chain response.

* QNAME(final):实际解析的名称,即实际查询的名称或CNAME链响应中的姓氏。

Note that, because the definition in [RFC2308] is actually for a different concept than what was in [RFC1034], it would have been better if [RFC2308] had used a different name for that concept.


In general use today, QNAME almost always means what is defined above as "QNAME (original)".


Referrals: A type of response in which a server, signaling that it is not (completely) authoritative for an answer, provides the querying resolver with an alternative place to send its query. Referrals can be partial.


A referral arises when a server is not performing recursive service while answering a query. It appears in step 3(b) of the algorithm in [RFC1034], Section 4.3.2.


There are two types of referral response. The first is a downward referral (sometimes described as "delegation response"), where the server is authoritative for some portion of the QNAME. The authority section RRset's RDATA contains the name servers specified at the referred-to zone cut. In normal DNS operation, this kind of response is required in order to find names beneath a delegation. The bare use of "referral" means this kind of referral, and many people believe that this is the only legitimate kind of referral in the DNS.


The second is an upward referral (sometimes described as "root referral"), where the server is not authoritative for any portion of the QNAME. When this happens, the referred-to zone in the authority section is usually the root zone ("."). In normal DNS operation, this kind of response is not required for resolution or for correctly answering any query. There is no requirement that any server send upward referrals. Some people regard upward referrals as a sign of a misconfiguration or error. Upward referrals always need some sort of qualifier (such as "upward" or "root") and are never identified simply by the word "referral".


A response that has only a referral contains an empty answer section. It contains the NS RRset for the referred-to zone in the Authority section. It may contain RRs that provide addresses in the additional section. The AA bit is clear.

只有引用的响应包含一个空的应答部分。它包含权限部分中所指区域的NS RRset。它可能包含在附加部分中提供地址的RRs。AA位是明确的。

In the case where the query matches an alias, and the server is not authoritative for the target of the alias but is authoritative for some name above the target of the alias, the resolution algorithm will produce a response that contains both the authoritative answer for the alias and a referral. Such a partial answer and referral response has data in the Answer section. It has the NS RRset for the referred-to zone in the Authority section. It may contain RRs that provide addresses in the


additional section. The AA bit is set, because the first name in the Answer section matches the QNAME and the server is authoritative for that answer (see [RFC1035], Section 4.1.1).


5. Resource Records
5. 资源记录

RR: An acronym for resource record. (See [RFC1034], Section 3.6.)


RRset: A set of resource records "with the same label, class and type, but with different data" (according to [RFC2181], Section 5). Also written as "RRSet" in some documents. As a clarification, "same label" in this definition means "same owner name". In addition, [RFC2181] states that "the TTLs of all RRs in an RRSet must be the same".


Note that RRSIG resource records do not match this definition. [RFC4035] says:


An RRset MAY have multiple RRSIG RRs associated with it. Note that as RRSIG RRs are closely tied to the RRsets whose signatures they contain, RRSIG RRs, unlike all other DNS RR types, do not form RRsets. In particular, the TTL values among RRSIG RRs with a common owner name do not follow the RRset rules described in [RFC2181].

一个RRset可能有多个与之关联的RRSIG RRs。请注意,由于RRSIG RRs与包含其签名的RRSET密切相关,因此与所有其他DNS RR类型不同,RRSIG RRs不构成RRSET。特别是,具有公共所有者名称的RRSIG RRs中的TTL值不遵循[RFC2181]中描述的RRset规则。

Master file: "Master files are text files that contain RRs in text form. Since the contents of a zone can be expressed in the form of a list of RRs a master file is most often used to define a zone, though it can be used to list a cache's contents." (Quoted from [RFC1035], Section 5) Master files are sometimes called "zone files".


Presentation format: The text format used in master files. This format is shown but not formally defined in [RFC1034] or [RFC1035]. The term "presentation format" first appears in [RFC4034].


EDNS: The extension mechanisms for DNS, defined in [RFC6891]. Sometimes called "EDNS0" or "EDNS(0)" to indicate the version number. EDNS allows DNS clients and servers to specify message sizes larger than the original 512 octet limit, to expand the response code space and to carry additional options that affect the handling of a DNS query.


OPT: A pseudo-RR (sometimes called a "meta-RR") that is used only to contain control information pertaining to the question-and-answer sequence of a specific transaction. (Definition paraphrased from [RFC6891], Section 6.1.1.) It is used by EDNS.

OPT:一种伪RR(有时称为“meta RR”),仅用于包含与特定事务的问答顺序相关的控制信息。(定义摘自[RFC6891]第6.1.1节)。EDN使用该定义。

Owner: "The domain name where the RR is found." (Quoted from [RFC1034], Section 3.6) Often appears in the term "owner name".


SOA field names: DNS documents, including the definitions here, often refer to the fields in the RDATA of an SOA resource record by field name. "SOA" stands for "start of a zone of authority". Those fields are defined in Section 3.3.13 of [RFC1035]. The names (in the order they appear in the SOA RDATA) are MNAME, RNAME, SERIAL, REFRESH, RETRY, EXPIRE, and MINIMUM. Note that the meaning of the MINIMUM field is updated in Section 4 of [RFC2308]; the new definition is that the MINIMUM field is only "the TTL to be used for negative responses". This document tends to use field names instead of terms that describe the fields.

SOA字段名:DNS文档(包括此处的定义)通常按字段名引用SOA资源记录的RDATA中的字段。“SOA”代表“权威区域的开始”。这些字段在[RFC1035]第3.3.13节中定义。名称(按照它们在SOA RDATA中出现的顺序)是MNAME、RNAME、SERIAL、REFRESH、RETRY、EXPIRE和MINIMUM。注意,[RFC2308]第4节更新了最小字段的含义;新的定义是,最小字段仅为“用于负面响应的TTL”。本文档倾向于使用字段名,而不是描述字段的术语。

TTL: The maximum "time to live" of a resource record. "A TTL value is an unsigned number, with a minimum value of 0, and a maximum value of 2147483647. That is, a maximum of 2^31 - 1. When transmitted, this value shall be encoded in the less significant 31 bits of the 32 bit TTL field, with the most significant, or sign, bit set to zero." (Quoted from [RFC2181], Section 8) (Note that [RFC1035] erroneously stated that this is a signed integer; that was fixed by [RFC2181].)


The TTL "specifies the time interval that the resource record may be cached before the source of the information should again be consulted." (Quoted from [RFC1035], Section 3.2.1) Section 4.1.3 of the same document states: "the time interval (in seconds) that the resource record may be cached before it should be discarded". Despite being defined for a resource record, the TTL of every resource record in an RRset is required to be the same ([RFC2181], Section 5.2).


The reason that the TTL is the maximum time to live is that a cache operator might decide to shorten the time to live for operational purposes, such as if there is a policy to disallow TTL values over a certain number. Some servers are known to ignore the TTL on some RRsets (such as when the authoritative data has a very short TTL) even though this is against the advice in RFC 1035. An RRset can be flushed from the cache before the end of the TTL interval, at which point, the value of the TTL becomes unknown because the RRset with which it was associated no longer exists.

TTL是最长生存时间的原因是缓存操作员可能会出于操作目的决定缩短生存时间,例如,如果有策略不允许TTL值超过某个数字。已知有些服务器会忽略某些RRSET上的TTL(例如,当权威数据具有非常短的TTL时),即使这违反了RFC 1035中的建议。可以在TTL间隔结束之前从缓存中刷新RRset,此时,TTL的值变得未知,因为与其关联的RRset不再存在。

There is also the concept of a "default TTL" for a zone, which can be a configuration parameter in the server software. This is often expressed by a default for the entire server, and a default for a zone using the $TTL directive in a zone file. The $TTL directive was added to the master file format by [RFC2308].


Class independent: A resource record type whose syntax and semantics are the same for every DNS class. A resource record type that is not class independent has different meanings depending on the DNS class of the record, or the meaning is undefined for some class. Most resource record types are defined for class 1 (IN, the Internet), but many are undefined for other classes.


Address records: Records whose type is A or AAAA. [RFC2181] informally defines these as "(A, AAAA, etc)". Note that new types of address records could be defined in the future.


6. DNS Servers and Clients
6. DNS服务器和客户端

This section defines the terms used for the systems that act as DNS clients, DNS servers, or both. In past RFCs, DNS servers are sometimes called "name servers", "nameservers", or just "servers". There is no formal definition of "DNS server", but RFCs generally assume that it is an Internet server that listens for queries and sends responses using the DNS protocol defined in [RFC1035] and its successors.


It is important to note that the terms "DNS server" and "name server" require context in order to understand the services being provided. Both authoritative servers and recursive resolvers are often called "DNS servers" and "name servers" even though they serve different roles (but may be part of the same software package).


For terminology specific to the public DNS root server system, see [RSSAC026]. That document defines terms such as "root server", "root server operator", and terms that are specific to the way that the root zone of the public DNS is served.


Resolver: A program "that extract[s] information from name servers in response to client requests." (Quoted from [RFC1034], Section 2.4) A resolver performs queries for a name, type, and class, and receives responses. The logical function is called "resolution". In practice, the term is usually referring to some specific type of resolver (some of which are defined below), and understanding the use of the term depends on understanding the context.


A related term is "resolve", which is not formally defined in [RFC1034] or [RFC1035]. An imputed definition might be "asking a question that consists of a domain name, class, and type, and receiving some sort of response". Similarly, an imputed definition of "resolution" might be "the response received from resolving".


Stub resolver: A resolver that cannot perform all resolution itself. Stub resolvers generally depend on a recursive resolver to undertake the actual resolution function. Stub resolvers are discussed but never fully defined in Section 5.3.1 of [RFC1034]. They are fully defined in Section of [RFC1123].


Iterative mode: A resolution mode of a server that receives DNS queries and responds with a referral to another server. Section 2.3 of [RFC1034] describes this as "The server refers the client to another server and lets the client pursue the query." A resolver that works in iterative mode is sometimes called an "iterative resolver". See also "iterative resolution" later in this section.


Recursive mode: A resolution mode of a server that receives DNS queries and either responds to those queries from a local cache or sends queries to other servers in order to get the final answers to the original queries. Section 2.3 of [RFC1034] describes this as "the first server pursues the query for the client at another server". Section 4.3.1 of [RFC1034] says: "in [recursive] mode the name server acts in the role of a resolver and returns either an error or the answer, but never referrals." That same section also says:


The recursive mode occurs when a query with RD set arrives at a server which is willing to provide recursive service; the client can verify that recursive mode was used by checking that both RA and RD are set in the reply.


A server operating in recursive mode may be thought of as having a name server side (which is what answers the query) and a resolver side (which performs the resolution function). Systems operating in this mode are commonly called "recursive servers". Sometimes they are called "recursive resolvers". In practice, it is not possible to know in advance whether the server that one is querying will also perform recursion; both terms can be observed in use interchangeably.


Recursive resolver: A resolver that acts in recursive mode. In general, a recursive resolver is expected to cache the answers it receives (which would make it a full-service resolver), but some recursive resolvers might not cache.


[RFC4697] tried to differentiate between a recursive resolver and an iterative resolver.


Recursive query: A query with the Recursion Desired (RD) bit set to 1 in the header. (See Section 4.1.1 of [RFC1035].) If recursive service is available and is requested by the RD bit in the query, the server uses its resolver to answer the query. (See Section 4.3.2 of [RFC1034].)


Non-recursive query: A query with the Recursion Desired (RD) bit set to 0 in the header. A server can answer non-recursive queries using only local information: the response contains either an error, the answer, or a referral to some other server "closer" to the answer. (See Section 4.3.1 of [RFC1034].)


Iterative resolution: A name server may be presented with a query that can only be answered by some other server. The two general approaches to dealing with this problem are "recursive", in which the first server pursues the query on behalf of the client at another server, and "iterative", in which the server refers the client to another server and lets the client pursue the query there. (See Section 2.3 of [RFC1034].)


In iterative resolution, the client repeatedly makes non-recursive queries and follows referrals and/or aliases. The iterative resolution algorithm is described in Section 5.3.3 of [RFC1034].


Full resolver: This term is used in [RFC1035], but it is not defined there. RFC 1123 defines a "full-service resolver" that may or may not be what was intended by "full resolver" in [RFC1035]. This term is not properly defined in any RFC.

完全解析程序:此术语在[RFC1035]中使用,但未在其中定义。RFC 1123定义了一个“全服务解析器”,它可能是也可能不是[RFC1035]中“全服务解析器”所期望的。该术语未在任何RFC中正确定义。

Full-service resolver: Section of [RFC1123] defines this term to mean a resolver that acts in recursive mode with a cache (and meets other requirements).


Priming: "The act of finding the list of root servers from a configuration that lists some or all of the purported IP addresses of some or all of those root servers." (Quoted from [RFC8109], Section 2) In order to operate in recursive mode, a resolver needs to know the address of at least one root server. Priming is most often done from a configuration setting that contains a list of authoritative servers for the root zone.


Root hints: "Operators who manage a DNS recursive resolver typically need to configure a 'root hints file'. This file contains the names and IP addresses of the authoritative name servers for the root zone, so the software can bootstrap the DNS resolution process. For many pieces of software, this list comes built into the software." (Quoted from [IANA_RootFiles]) This file is often used in priming.


Negative caching: "The storage of knowledge that something does not exist, cannot or does not give an answer." (Quoted from [RFC2308], Section 1)


Authoritative server: "A server that knows the content of a DNS zone from local knowledge, and thus can answer queries about that zone without needing to query other servers." (Quoted from [RFC2182], Section 2) An authoritative server is named in the NS ("name server") record in a zone. It is a system that responds to DNS queries with information about zones for which it has been configured to answer with the AA flag in the response header set to 1. It is a server that has authority over one or more DNS zones. Note that it is possible for an authoritative server to respond to a query without the parent zone delegating authority to that server. Authoritative servers also provide "referrals", usually to child zones delegated from them; these referrals have the AA bit set to 0 and come with referral data in the Authority and (if needed) the Additional sections.


Authoritative-only server: A name server that only serves authoritative data and ignores requests for recursion. It will "not normally generate any queries of its own. Instead it answers non-recursive queries from iterative resolvers looking for information in zones it serves." (Quoted from [RFC4697], Section 2.4) In this case, "ignores requests for recursion" means "responds to requests for recursion with responses indicating that recursion was not performed".


Zone transfer: The act of a client requesting a copy of a zone and an authoritative server sending the needed information. (See Section 7 for a description of zones.) There are two common standard ways to do zone transfers: the AXFR ("Authoritative Transfer") mechanism to copy the full zone (described in [RFC5936], and the IXFR ("Incremental Transfer") mechanism to copy only parts of the zone that have changed (described in [RFC1995]). Many systems use non-standard methods for zone transfer outside the DNS protocol.


Slave server: See "Secondary server".


Secondary server: "An authoritative server which uses zone transfer to retrieve the zone." (Quoted from [RFC1996], Section 2.1) Secondary servers are also discussed in [RFC1034]. [RFC2182] describes secondary servers in more detail. Although early DNS RFCs such as [RFC1996] referred to this as a "slave", the current common usage has shifted to calling it a "secondary".

辅助服务器:“使用区域传输检索区域的权威服务器。”(引用[RFC1996]第2.1节)辅助服务器也在[RFC1034]中讨论。[RFC2182]更详细地描述了辅助服务器。尽管早期的DNS RFC(如[RFC1996])将其称为“从属”,但当前的常见用法已转变为将其称为“辅助”。

Master server: See "Primary server".


Primary server: "Any authoritative server configured to be the source of zone transfer for one or more [secondary] servers." (Quoted from [RFC1996], Section 2.1) Or, more specifically, [RFC2136] calls it "an authoritative server configured to be the source of AXFR or IXFR data for one or more [secondary] servers". Primary servers are also discussed in [RFC1034]. Although early DNS RFCs such as [RFC1996] referred to this as a "master", the current common usage has shifted to "primary".

主服务器:“配置为一个或多个[辅助]服务器的区域传输源的任何权威服务器。”(引自[RFC1996],第2.1节),或者更具体地说,[RFC2136]将其称为“配置为一个或多个[辅助]服务器的AXFR或IXFR数据源的权威服务器”。[RFC1034]中还讨论了主服务器。尽管早期的DNS RFC(如[RFC1996])将其称为“主机”,但当前的常用用法已转移到“主”。

Primary master: "The primary master is named in the zone's SOA MNAME field and optionally by an NS RR." (Quoted from [RFC1996], Section 2.1) [RFC2136] defines "primary master" as "Master server at the root of the AXFR/IXFR dependency graph. The primary master is named in the zone's SOA MNAME field and optionally by an NS RR. There is by definition only one primary master server per zone."

主主控台:“主控台在区域的SOA MNAME字段中命名,可选地由NS RR命名。”(引用自[RFC1996],第2.1节)[RFC2136]将“主控台”定义为“位于AXFR/IXFR依赖关系图根目录下的主服务器。主主机在区域的SOA MNAME字段中命名,也可以由NS RR命名。根据定义,每个区域只有一个主主服务器。“

The idea of a primary master is only used in [RFC1996] and [RFC2136]. A modern interpretation of the term "primary master" is a server that is both authoritative for a zone and that gets its updates to the zone from configuration (such as a master file) or from UPDATE transactions.


Stealth server: This is "like a slave server except not listed in an NS RR for the zone." (Quoted from [RFC1996], Section 2.1)

隐形服务器:这“与从属服务器类似,但未在区域的NS RR中列出。”(引自[RFC1996],第2.1节)

Hidden master: A stealth server that is a primary server for zone transfers. "In this arrangement, the master name server that processes the updates is unavailable to general hosts on the Internet; it is not listed in the NS RRset." (Quoted from [RFC6781], Section 3.4.3) An earlier RFC, [RFC4641], said that the hidden master's name "appears in the SOA RRs MNAME field", although, in some setups, the name does not appear at all in the public DNS. A hidden master can also be a secondary server for the zone itself.

隐藏主机:作为区域传输主服务器的隐藏服务器。“在这种安排中,处理更新的主机名服务器对Internet上的普通主机不可用;它未列在NS RRset中。”(引用[RFC6781],第3.4.3节)早期的RFC[RFC4641]说,隐藏的主机名“出现在SOA RRs MNAME字段中”,尽管在某些设置中,该名称根本不出现在公共DNS中。隐藏的主服务器也可以是区域本身的辅助服务器。

Forwarding: The process of one server sending a DNS query with the RD bit set to 1 to another server to resolve that query. Forwarding is a function of a DNS resolver; it is different than simply blindly relaying queries.


[RFC5625] does not give a specific definition for forwarding, but describes in detail what features a system that forwards needs to support. Systems that forward are sometimes called "DNS proxies", but that term has not yet been defined (even in [RFC5625]).


Forwarder: Section 1 of [RFC2308] describes a forwarder as "a nameserver used to resolve queries instead of directly using the authoritative nameserver chain". [RFC2308] further says "The forwarder typically either has better access to the internet, or maintains a bigger cache which may be shared amongst many resolvers." That definition appears to suggest that forwarders normally only query authoritative servers. In current use, however, forwarders often stand between stub resolvers and recursive servers. [RFC2308] is silent on whether a forwarder is iterative-only or can be a full-service resolver.


Policy-implementing resolver: A resolver acting in recursive mode that changes some of the answers that it returns based on policy criteria, such as to prevent access to malware sites or objectionable content. In general, a stub resolver has no idea whether upstream resolvers implement such policy or, if they do, the exact policy about what changes will be made. In some cases, the user of the stub resolver has selected the policy-implementing resolver with the explicit intention of using it to implement the policies. In other cases, policies are imposed without the user of the stub resolver being informed.


Open resolver: A full-service resolver that accepts and processes queries from any (or nearly any) client. This is sometimes also called a "public resolver", although the term "public resolver" is used more with open resolvers that are meant to be open, as compared to the vast majority of open resolvers that are probably misconfigured to be open. Open resolvers are discussed in [RFC5358].


Split DNS: The terms "split DNS" and "split-horizon DNS" have long been used in the DNS community without formal definition. In general, they refer to situations in which DNS servers that are authoritative for a particular set of domains provide partly or completely different answers in those domains depending on the source of the query. The effect of this is that a domain name that is notionally globally unique nevertheless has different meanings for different network users. This can sometimes be the result of a "view" configuration, described below.


Section 3.8 of [RFC2775] gives a related definition that is too specific to be generally useful.


View: A configuration for a DNS server that allows it to provide different responses depending on attributes of the query, such as for "split DNS". Typically, views differ by the source IP address of a query, but can also be based on the destination IP address, the type of query (such as AXFR), whether it is recursive, and so


on. Views are often used to provide more names or different addresses to queries from "inside" a protected network than to those "outside" that network. Views are not a standardized part of the DNS, but they are widely implemented in server software.


Passive DNS: A mechanism to collect DNS data by storing DNS responses from name servers. Some of these systems also collect the DNS queries associated with the responses, although doing so raises some privacy concerns. Passive DNS databases can be used to answer historical questions about DNS zones such as which values were present at a given time in the past, or when a name was spotted first. Passive DNS databases allow searching of the stored records on keys other than just the name and type, such as "find all names which have A records of a particular value".


Anycast: "The practice of making a particular service address available in multiple, discrete, autonomous locations, such that datagrams sent are routed to one of several available locations." (Quoted from [RFC4786], Section 2) See [RFC4786] for more detail on Anycast and other terms that are specific to its use.


Instance: "When anycast routing is used to allow more than one server to have the same IP address, each one of those servers is commonly referred to as an 'instance'." It goes on to say: "An instance of a server, such as a root server, is often referred to as an 'Anycast instance'." (Quoted from [RSSAC026])


Privacy-enabling DNS server: "A DNS server that implements DNS over TLS [RFC7858] and may optionally implement DNS over DTLS [RFC8094]." (Quoted from [RFC8310], Section 2) Other types of DNS servers might also be considered privacy-enabling, such as those running DNS over HTTPS [RFC8484].


7. Zones
7. 地带

This section defines terms that are used when discussing zones that are being served or retrieved.


Zone: "Authoritative information is organized into units called ZONEs, and these zones can be automatically distributed to the name servers which provide redundant service for the data in a zone." (Quoted from [RFC1034], Section 2.4)


Child: "The entity on record that has the delegation of the domain from the Parent." (Quoted from [RFC7344], Section 1.1)


Parent: "The domain in which the Child is registered." (Quoted from [RFC7344], Section 1.1) Earlier, "parent name server" was defined in [RFC0882] as "the name server that has authority over the place in the domain name space that will hold the new domain". (Note that [RFC0882] was obsoleted by [RFC1034] and [RFC1035].) [RFC819] also has some description of the relationship between parents and children.




There are two different uses for this term:


(a) "The domain name that appears at the top of a zone (just below the cut that separates the zone from its parent)... The name of the zone is the same as the name of the domain at the zone's origin." (Quoted from [RFC2181], Section 6) These days, this sense of "origin" and "apex" (defined below) are often used interchangeably.

(a) “出现在分区顶部的域名(位于分区与其父分区之间的切口的正下方)……分区的名称与分区原点的域名相同。”(引用自[RFC2181],第6节)如今,“原点”和“顶点”(定义见下文)这两种含义经常互换使用。

(b) The domain name within which a given relative domain name appears in zone files. Generally seen in the context of "$ORIGIN", which is a control entry defined in [RFC1035], Section 5.1, as part of the master file format. For example, if the $ORIGIN is set to "", then a master file line for "www" is in fact an entry for "".

(b) 区域文件中显示给定相对域名的域名。通常在“$ORIGIN”上下文中看到,这是[RFC1035]第5.1节中定义的控制项,作为主文件格式的一部分。例如,如果$ORIGIN设置为“”,那么“www”的主文件行实际上是“”的条目。

Apex: The point in the tree at an owner of an SOA and corresponding authoritative NS RRset. This is also called the "zone apex". [RFC4033] defines it as "the name at the child's side of a zone cut". The "apex" can usefully be thought of as a data-theoretic description of a tree structure, and "origin" is the name of the same concept when it is implemented in zone files. The distinction is not always maintained in use, however, and one can find uses that conflict subtly with this definition. [RFC1034] uses the term "top node of the zone" as a synonym of "apex", but that term is not widely used. These days, the first sense of "origin" (above) and "apex" are often used interchangeably.


Zone cut: The delimitation point between two zones where the origin of one of the zones is the child of the other zone.


"Zones are delimited by 'zone cuts'. Each zone cut separates a 'child' zone (below the cut) from a 'parent' zone (above the cut)." (Quoted from [RFC2181], Section 6; note that this is barely an ostensive definition.) Section 4.2 of [RFC1034] uses "cuts" instead of "zone cut".


Delegation: The process by which a separate zone is created in the name space beneath the apex of a given domain. Delegation happens when an NS RRset is added in the parent zone for the child origin. Delegation inherently happens at a zone cut. The term is also commonly a noun: the new zone that is created by the act of delegating.

委派:在给定域顶点下的名称空间中创建单独区域的过程。在子原点的父区域中添加NS RRset时,会发生委派。授权通常发生在区域切割处。该术语通常也是一个名词:通过授权行为创建的新区域。

Authoritative data: "All of the RRs attached to all of the nodes from the top node of the zone down to leaf nodes or nodes above cuts around the bottom edge of the zone." (Quoted from [RFC1034], Section 4.2.1) Note that this definition might inadvertently also cause any NS records that appear in the zone to be included, even those that might not truly be authoritative because there are identical NS RRs below the zone cut. This reveals the ambiguity in the notion of authoritative data, because the parent-side NS records authoritatively indicate the delegation, even though they are not themselves authoritative data.

权威数据:“连接到所有节点的所有RRs,从区域顶部节点到叶节点或区域底部边缘周围切口上方的节点。”(引自[RFC1034],第4.2.1节)注意,该定义可能会无意中导致包含区域中出现的任何NS记录,即使那些可能不是真正权威的,因为在分区切割下有相同的NS RRs。这揭示了权威数据概念的模糊性,因为父端NS记录权威性地指示委托,即使它们本身不是权威数据。

[RFC4033], Section 2, defines "Authoritative RRset", which is related to authoritative data but has a more precise definition.


Lame delegation: "A lame delegations exists [sic] when a nameserver is delegated responsibility for providing nameservice for a zone (via NS records) but is not performing nameservice for that zone (usually because it is not set up as a primary or secondary for the zone)." (Quoted from [RFC1912], Section 2.8) Another definition is that a lame delegation "...happens when a name server is listed in the NS records for some domain and in fact it is not a server for that domain. Queries are thus sent to the wrong servers, who don't know nothing [sic] (at least not as expected) about the queried domain. Furthermore, sometimes these hosts (if they exist!) don't even run name servers." (Quoted from [RFC1713], Section 2.3)


Glue records: "...[Resource records] which are not part of the authoritative data [of the zone], and are address RRs for the [name] servers [in subzones]. These RRs are only necessary if the name server's name is 'below' the cut, and are only used as part of a referral response." Without glue "we could be faced with the situation where the NS RRs tell us that in order to learn a name server's address, we should contact the server using the address we wish to learn." (Quoted from [RFC1034], Section 4.2.1)

粘合记录:“…[资源记录]不属于[区域]的权威数据的一部分,并且是[子区域]中[名称]服务器的地址RRs。仅当名称服务器的名称位于剪切“下方”时,这些RRs才是必需的,并且仅用作引用响应的一部分。”“我们可能面临这样的情况:NS RRs告诉我们,为了了解名称服务器的地址,我们应该使用我们希望了解的地址与服务器联系。”(引自[RFC1034],第4.2.1节)

A later definition is that glue "includes any record in a zone file that is not properly part of that zone, including nameserver records of delegated sub-zones (NS records), address records that accompany those NS records (A, AAAA, etc), and any other stray data that might appear." (Quoted from [RFC2181], Section 5.4.1)


Although glue is sometimes used today with this wider definition in mind, the context surrounding the definition in [RFC2181] suggests it is intended to apply to the use of glue within the document itself and not necessarily beyond.


Bailiwick: "In-bailiwick" is a modifier to describe a name server whose name is either a subdomain of or (rarely) the same as the origin of the zone that contains the delegation to the name server. In-bailiwick name servers may have glue records in their parent zone (using the first of the definitions of "glue records" in the definition above). (The word "bailiwick" means the district or territory where a bailiff or policeman has jurisdiction.)

辖区:“In Bailiwick”是一个修饰符,用于描述名称服务器,其名称是名称服务器的子域,或者(很少)与包含对名称服务器的委派的区域的原点相同。在辖区内,名称服务器的父区域中可能有粘合记录(使用上述定义中“粘合记录”的第一个定义)。(单词“辖区”指执达主任或警察拥有管辖权的地区或地区。)

"In-bailiwick" names are divided into two types of names for name servers: "in-domain" names and "sibling domain" names.


* In-domain: a modifier to describe a name server whose name is either subordinate to or (rarely) the same as the owner name of the NS resource records. An in-domain name server name needs to have glue records or name resolution fails. For example, a delegation for "" may have "in-domain" name server name "".

* 域内:一个修饰符,用于描述名称服务器,其名称从属于或(很少)与NS资源记录的所有者名称相同。域名内服务器名称需要有粘合记录,否则名称解析失败。例如,“”的委托可能具有“域内”名称服务器名“”。

* Sibling domain: a name server's name that is either subordinate to or (rarely) the same as the zone origin and not subordinate to or the same as the owner name of the NS resource records. Glue records for sibling domains are allowed, but not necessary. For example, a delegation for "" in "" zone may have "sibling" name server name "".

* 同级域:名称服务器的名称,从属于或(很少)与区域源相同,但不从属于或与NS资源记录的所有者名称相同。允许兄弟域的粘合记录,但不是必需的。例如,“”区域中“”的委托可能具有“兄弟”名称服务器名称“”。

"Out-of-bailiwick" is the antonym of "in-bailiwick". It is a modifier to describe a name server whose name is not subordinate to or the same as the zone origin. Glue records for out-of-bailiwick name servers are useless. The following table shows examples of delegation types.


   Delegation |Parent|Name Server Name  | Type
   com        | .    ||in-bailiwick / sibling domain
   net        | .    ||in-bailiwick / in-domain| org  |    |in-bailiwick / in-domain| org  |       |in-bailiwick / sibling domain| org  |    |out-of-bailiwick | jp   |     |in-bailiwick / in-domain | jp   |  |in-bailiwick / sibling domain | jp   |    |out-of-bailiwick
   Delegation |Parent|Name Server Name  | Type
   com        | .    ||in-bailiwick / sibling domain
   net        | .    ||in-bailiwick / in-domain| org  |    |in-bailiwick / in-domain| org  |       |in-bailiwick / sibling domain| org  |    |out-of-bailiwick | jp   |     |in-bailiwick / in-domain | jp   |  |in-bailiwick / sibling domain | jp   |    |out-of-bailiwick

Root zone: The zone of a DNS-based tree whose apex is the zero-length label. Also sometimes called "the DNS root".


Empty non-terminals (ENT): "Domain names that own no resource records but have subdomains that do." (Quoted from [RFC4592], Section 2.2.2) A typical example is in SRV records: in the name "", it is likely that "" has no RRsets, but that "" has (at least) an SRV RRset.

空非终端(ENT):“不拥有资源记录但拥有子域的域名。”(引用[RFC4592],第2.2.2节)一个典型的例子是SRV记录:在名称“\u sip.\u”中,很可能“\u”没有RRset,但“\u sip.\u”至少有一个SRV RRset。

Delegation-centric zone: A zone that consists mostly of delegations to child zones. This term is used in contrast to a zone that might have some delegations to child zones but also has many data resource records for the zone itself and/or for child zones. The term is used in [RFC4956] and [RFC5155], but it is not defined in either document.


Occluded name: "The addition of a delegation point via dynamic update will render all subordinate domain names to be in a limbo, still part of the zone but not available to the lookup process. The addition of a DNAME resource record has the same impact. The subordinate names are said to be 'occluded'." (Quoted from [RFC5936], Section 3.5)


Fast flux DNS: This "occurs when a domain is [found] in DNS using A records to multiple IP addresses, each of which has a very short Time-to-Live (TTL) value associated with it. This means that the domain resolves to varying IP addresses over a short period of time." (Quoted from [RFC6561], Section 1.1.5, with a typo corrected) In addition to having legitimate uses, fast flux DNS can used to deliver malware. Because the addresses change so rapidly, it is difficult to ascertain all the hosts. It should be noted that the technique also works with AAAA records, but such use is not frequently observed on the Internet as of this writing.

Fast flux DNS:当在DNS中使用多个IP地址的记录[找到]一个域时,就会发生这种情况,每个IP地址都有一个非常短的生存时间(TTL)值与之关联。这意味着该域在短时间内解析为不同的IP地址。(引用[RFC6561],第1.1.5节,并更正打字错误)除了合法使用外,fast flux DNS还可用于交付恶意软件。由于地址变化太快,很难确定所有主机。应该注意的是,该技术也适用于AAAA记录,但在撰写本文时,互联网上并不经常观察到这种使用。

Reverse DNS, reverse lookup: "The process of mapping an address to a name is generally known as a 'reverse lookup', and the IN-ADDR.ARPA and IP6.ARPA zones are said to support the 'reverse DNS'." (Quoted from [RFC5855], Section 1)


Forward lookup: "Hostname-to-address translation". (Quoted from [RFC3493], Section 6)


arpa: Address and Routing Parameter Area Domain: "The 'arpa' domain was originally established as part of the initial deployment of the DNS, to provide a transition mechanism from the Host Tables that were common in the ARPANET, as well as a home for the IPv4 reverse mapping domain. During 2000, the abbreviation was

arpa:Address and Routing Parameter Area Domain:“arpa”域最初是作为DNS初始部署的一部分建立的,用于提供从ARPANET中常见的主机表到IPv4反向映射域的转换机制。2000年期间,缩写为

redesignated to 'Address and Routing Parameter Area' in the hope of reducing confusion with the earlier network name." (Quoted from [RFC3172], Section 2) .arpa is an "infrastructure domain", a domain whose "role is to support the operating infrastructure of the Internet". (Quoted from [RFC3172], Section 2) See [RFC3172] for more history of this name.


Service name: "Service names are the unique key in the Service Name and Transport Protocol Port Number registry. This unique symbolic name for a service may also be used for other purposes, such as in DNS SRV records." (Quoted from [RFC6335], Section 5)

服务名称:“服务名称是服务名称和传输协议端口号注册表中的唯一项。服务的此唯一符号名称也可用于其他目的,例如在DNS SRV记录中。”(引用自[RFC6335],第5节)

8. Wildcards
8. 通配符

Wildcard: [RFC1034] defined "wildcard", but in a way that turned out to be confusing to implementers. For an extended discussion of wildcards, including clearer definitions, see [RFC4592]. Special treatment is given to RRs with owner names starting with the label "*". "Such RRs are called 'wildcards'. Wildcard RRs can be thought of as instructions for synthesizing RRs." (Quoted from [RFC1034], Section 4.3.3)


Asterisk label: "The first octet is the normal label type and length for a 1-octet-long label, and the second octet is the ASCII representation [RFC20] for the '*' character. A descriptive name of a label equaling that value is an 'asterisk label'." (Quoted from [RFC4592], Section 2.1.1)


Wildcard domain name: "A 'wildcard domain name' is defined by having its initial (i.e., leftmost or least significant) label, in binary format: 0000 0001 0010 1010 (binary) = 0x01 0x2a (hexadecimal)". (Quoted from [RFC4592], Section 2.1.1) The second octet in this label is the ASCII representation for the "*" character.

通配符域名:“一个‘通配符域名’的定义是,它的首字母(即最左边或最不重要的)标签采用二进制格式:0000 0001 0010 1010(二进制)=0x01 0x2a(十六进制)”。(引自[RFC4592]第2.1.1节)此标签中的第二个八位字节是“*”字符的ASCII表示。

Closest encloser: "The longest existing ancestor of a name." (Quoted from [RFC5155], Section 1.3) An earlier definition is "The node in the zone's tree of existing domain names that has the most labels matching the query name (consecutively, counting from the root label downward). Each match is a 'label match' and the order of the labels is the same." (Quoted from [RFC4592], Section 3.3.1)


Closest provable encloser: "The longest ancestor of a name that can be proven to exist. Note that this is only different from the closest encloser in an Opt-Out zone." (Quoted from [RFC5155], Section 1.3) See Section 10 for more on "opt-out".


Next closer name: "The name one label longer than the closest provable encloser of a name." (Quoted from [RFC5155], Section 1.3)


Source of Synthesis: "The source of synthesis is defined in the context of a query process as that wildcard domain name immediately descending from the closest encloser, provided that this wildcard domain name exists. 'Immediately descending' means that the source of synthesis has a name of the form: <asterisk label>.<closest encloser>." (Quoted from [RFC4592], Section 3.3.1)

合成源:“在查询过程的上下文中,合成源被定义为从最近的封闭器中立即递减的通配符域名,前提是该通配符域名存在。“立即递减”表示合成源的名称形式为:<asterisk label><closest封闭器>”(引自[RFC4592]第3.3.1节)

9. Registration Model
9. 注册模型

Registry: The administrative operation of a zone that allows registration of names within that zone. People often use this term to refer only to those organizations that perform registration in large delegation-centric zones (such as TLDs); but formally, whoever decides what data goes into a zone is the registry for that zone. This definition of "registry" is from a DNS point of view; for some zones, the policies that determine what can go in the zone are decided by zones that are superordinate and not the registry operator.


Registrant: An individual or organization on whose behalf a name in a zone is registered by the registry. In many zones, the registry and the registrant may be the same entity, but in TLDs they often are not.


Registrar: A service provider that acts as a go-between for registrants and registries. Not all registrations require a registrar, though it is common to have registrars involved in registrations in TLDs.


EPP: The Extensible Provisioning Protocol (EPP), which is commonly used for communication of registration information between registries and registrars. EPP is defined in [RFC5730].


WHOIS: A protocol specified in [RFC3912], often used for querying registry databases. WHOIS data is frequently used to associate registration data (such as zone management contacts) with domain names. The term "WHOIS data" is often used as a synonym for the registry database, even though that database may be served by different protocols, particularly RDAP. The WHOIS protocol is also used with IP address registry data.


RDAP: The Registration Data Access Protocol, defined in [RFC7480], [RFC7481], [RFC7482], [RFC7483], [RFC7484], and [RFC7485]. The RDAP protocol and data format are meant as a replacement for WHOIS.


DNS operator: An entity responsible for running DNS servers. For a zone's authoritative servers, the registrant may act as their own DNS operator, their registrar may do it on their behalf, or they may use a third-party operator. For some zones, the registry function is performed by the DNS operator plus other entities who decide about the allowed contents of the zone.


Public suffix: "A domain that is controlled by a public registry." (Quoted from [RFC6265], Section 5.3) A common definition for this term is a domain under which subdomains can be registered by third parties and on which HTTP cookies (which are described in detail in [RFC6265]) should not be set. There is no indication in a domain name whether it is a public suffix; that can only be determined by outside means. In fact, both a domain and a subdomain of that domain can be public suffixes.

公共后缀:“由公共注册表控制的域。”(引用自[RFC6265],第5.3节)该术语的通用定义是一个域,第三方可以在该域下注册子域,并且不应在该域上设置HTTP cookie(详见[RFC6265])。域名中没有表明它是否为公共后缀;这只能通过外部手段来确定。事实上,域和该域的子域都可以是公共后缀。

There is nothing inherent in a domain name to indicate whether it is a public suffix. One resource for identifying public suffixes is the Public Suffix List (PSL) maintained by Mozilla (


For example, at the time this document is published, the "" domain is listed as a public suffix in the PSL. (Note that this example might change in the future.)


Note that the term "public suffix" is controversial in the DNS community for many reasons, and it may be significantly changed in the future. One example of the difficulty of calling a domain a public suffix is that designation can change over time as the registration policy for the zone changes, such as was the case with the "uk" TLD in 2014.


Subordinate and Superordinate: These terms are introduced in [RFC5731] for use in the registration model, but not defined there. Instead, they are given in examples. "For example, domain name '' has a superordinate relationship to host name'... For example, host is a subordinate host of domain, but it is a not a subordinate host of domain" (Quoted from [RFC5731], Section 1.1) These terms are strictly ways of referring to the relationship standing of two domains where one is a subdomain of the other.


10. General DNSSEC
10. DNSSEC将军

Most DNSSEC terms are defined in [RFC4033], [RFC4034], [RFC4035], and [RFC5155]. The terms that have caused confusion in the DNS community are highlighted here.


DNSSEC-aware and DNSSEC-unaware: These two terms, which are used in some RFCs, have not been formally defined. However, Section 2 of [RFC4033] defines many types of resolvers and validators, including "non-validating security-aware stub resolver", "non-validating stub resolver", "security-aware name server", "security-aware recursive name server", "security-aware resolver", "security-aware stub resolver", and "security-oblivious 'anything'". (Note that the term "validating resolver", which is used in some places in DNSSEC-related documents, is also not defined in those RFCs, but is defined below.)


Signed zone: "A zone whose RRsets are signed and that contains properly constructed DNSKEY, Resource Record Signature (RRSIG), Next Secure (NSEC), and (optionally) DS records." (Quoted from [RFC4033], Section 2) It has been noted in other contexts that the zone itself is not really signed, but all the relevant RRsets in the zone are signed. Nevertheless, if a zone that should be signed contains any RRsets that are not signed (or opted out), those RRsets will be treated as bogus, so the whole zone needs to be handled in some way.


It should also be noted that, since the publication of [RFC6840], NSEC records are no longer required for signed zones: a signed zone might include NSEC3 records instead. [RFC7129] provides additional background commentary and some context for the NSEC and NSEC3 mechanisms used by DNSSEC to provide authenticated denial-of-existence responses. NSEC and NSEC3 are described below.


Unsigned zone: Section 2 of [RFC4033] defines this as "a zone that is not signed". Section 2 of [RFC4035] defines this as a "zone that does not include these records [properly constructed DNSKEY, Resource Record Signature (RRSIG), Next Secure (NSEC), and (optionally) DS records] according to the rules in this section..." There is an important note at the end of Section 5.2 of [RFC4035] that defines an additional situation in which a zone is considered unsigned: "If the resolver does not support any of the algorithms listed in an authenticated DS RRset, then the resolver will not be able to verify the authentication path to the child zone. In this case, the resolver SHOULD treat the child zone as if it were unsigned."

未签名区域:[RFC4033]第2节将其定义为“未签名区域”。[RFC4035]第2节将其定义为“根据本节规则,不包括这些记录[正确构造的DNSKEY、资源记录签名(RRSIG)、下一安全(NSEC)和(可选)DS记录]的区域……”[RFC4035]第5.2节末尾有一个重要注释这定义了区域被视为未签名的另一种情况:“如果冲突解决程序不支持经过身份验证的DS RRset中列出的任何算法,则冲突解决程序将无法验证到子区域的身份验证路径。在这种情况下,冲突解决程序应将子区域视为未签名。”

NSEC: "The NSEC record allows a security-aware resolver to authenticate a negative reply for either name or type non-existence with the same mechanisms used to authenticate other DNS replies." (Quoted from [RFC4033], Section 3.2) In short, an NSEC record provides authenticated denial of existence.


"The NSEC resource record lists two separate things: the next owner name (in the canonical ordering of the zone) that contains authoritative data or a delegation point NS RRset, and the set of RR types present at the NSEC RR's owner name." (Quoted from Section 4 of RFC 4034)

“NSEC资源记录列出了两个独立的内容:包含权威数据或授权点NS RRset的下一个所有者名称(按照区域的规范顺序),以及NSEC RR所有者名称中存在的RR类型集。”(引自RFC 4034第4节)

NSEC3: Like the NSEC record, the NSEC3 record also provides authenticated denial of existence; however, NSEC3 records mitigate zone enumeration and support Opt-Out. NSEC3 resource records require associated NSEC3PARAM resource records. NSEC3 and NSEC3PARAM resource records are defined in [RFC5155].


Note that [RFC6840] says that [RFC5155] "is now considered part of the DNS Security Document Family as described by Section 10 of [RFC4033]". This means that some of the definitions from earlier RFCs that only talk about NSEC records should probably be considered to be talking about both NSEC and NSEC3.


Opt-out: "The Opt-Out Flag indicates whether this NSEC3 RR may cover unsigned delegations." (Quoted from [RFC5155], Section Opt-out tackles the high costs of securing a delegation to an insecure zone. When using Opt-Out, names that are an insecure delegation (and empty non-terminals that are only derived from insecure delegations) don't require an NSEC3 record or its corresponding RRSIG records. Opt-Out NSEC3 records are not able to prove or deny the existence of the insecure delegations. (Adapted from [RFC7129], Section 5.1)

选择退出:“选择退出标志表明NSEC3 RR是否包括未签署的授权。”(引自[RFC5155],第3.1.2.1节)选择退出解决了将授权固定到不安全区域的高成本问题。使用选择退出时,属于不安全委派的名称(以及仅从不安全委派派生的空非终端)不需要NSEC3记录或其相应的RRSIG记录。选择退出NSEC3记录无法证明或否认不安全授权的存在。(改编自[RFC7129],第5.1节)

Insecure delegation: "A signed name containing a delegation (NS RRset), but lacking a DS RRset, signifying a delegation to an unsigned subzone." (Quoted from [RFC4956], Section 2)

不安全的委托:“包含委托(NS RRset)但缺少DS RRset的签名名称,表示委托给未签名的子区域。”(引自[RFC4956]第2节)

Zone enumeration: "The practice of discovering the full content of a zone via successive queries." (Quoted from [RFC5155], Section 1.3) This is also sometimes called "zone walking". Zone enumeration is different from zone content guessing where the guesser uses a large dictionary of possible labels and sends successive queries for them, or matches the contents of NSEC3 records against such a dictionary.


Validation: Validation, in the context of DNSSEC, refers to one of the following:


* Checking the validity of DNSSEC signatures,

* 检查DNSSEC签名的有效性,

* Checking the validity of DNS responses, such as those including authenticated denial of existence, or

* 检查DNS响应的有效性,例如那些包括已验证的拒绝存在的响应,或

* Building an authentication chain from a trust anchor to a DNS response or individual DNS RRsets in a response

* 构建从信任锚点到DNS响应或响应中单个DNS RRSET的身份验证链

The first two definitions above consider only the validity of individual DNSSEC components such as the RRSIG validity or NSEC proof validity. The third definition considers the components of the entire DNSSEC authentication chain; thus, it requires "configured knowledge of at least one authenticated DNSKEY or DS RR" (as described in [RFC4035], Section 5).

上面的前两个定义仅考虑单个DNSSEC组件的有效性,例如RRSIG有效性或NSEC证明有效性。第三个定义考虑了整个DNSSEC认证链的组成部分;因此,它需要“至少一个经过身份验证的DNSKEY或DS RR的配置知识”(如[RFC4035]第5节所述)。

[RFC4033], Section 2, says that a "Validating Security-Aware Stub Resolver... performs signature validation" and uses a trust anchor "as a starting point for building the authentication chain to a signed DNS response"; thus, it uses the first and third definitions above. The process of validating an RRSIG resource record is described in [RFC4035], Section 5.3.


[RFC5155] refers to validating responses throughout the document, in the context of hashed authenticated denial of existence; this uses the second definition above.


The term "authentication" is used interchangeably with "validation", in the sense of the third definition above. [RFC4033], Section 2, describes the chain linking trust anchor to DNS data as the "authentication chain". A response is considered to be authentic if "all RRsets in the Answer and Authority sections of the response [are considered] to be authentic" (Quoted from [RFC4035]) DNS data or responses deemed to be authentic or validated have a security status of "secure" ([RFC4035], Section 4.3; [RFC4033], Section 5). "Authenticating both DNS keys and data is a matter of local policy, which may extend or even override the [DNSSEC] protocol extensions..." (Quoted from [RFC4033], Section 3.1)


The term "verification", when used, is usually a synonym for "validation".


Validating resolver: A security-aware recursive name server, security-aware resolver, or security-aware stub resolver that is applying at least one of the definitions of validation (above), as appropriate to the resolution context. For the same reason that the generic term "resolver" is sometimes ambiguous and needs to be evaluated in context (see Section 6), "validating resolver" is a context-sensitive term.


Key signing key (KSK): DNSSEC keys that "only sign the apex DNSKEY RRset in a zone." (Quoted from [RFC6781], Section 3.1)

密钥签名密钥(KSK):DNSSEC密钥,“仅对区域中的顶点DNSKEY RRset进行签名。”(引自[RFC6781],第3.1节)

Zone signing key (ZSK): "DNSSEC keys that can be used to sign all the RRsets in a zone that require signatures, other than the apex DNSKEY RRset." (Quoted from [RFC6781], Section 3.1) Also note that a ZSK is sometimes used to sign the apex DNSKEY RRset.

区域签名密钥(ZSK):“可用于对需要签名的区域中的所有RRset(apex DNSKEY RRset除外)进行签名的DNSSEC密钥。”(引自[RFC6781],第3.1节)还请注意,ZSK有时用于对apex DNSKEY RRset进行签名。

Combined signing key (CSK): "In cases where the differentiation between the KSK and ZSK is not made, i.e., where keys have the role of both KSK and ZSK, we talk about a Single-Type Signing Scheme." (Quoted from [RFC6781], Section 3.1) This is sometimes called a "combined signing key" or "CSK". It is operational practice, not protocol, that determines whether a particular key is a ZSK, a KSK, or a CSK.


   Secure Entry Point (SEP):  A flag in the DNSKEY RDATA that "can be
      used to distinguish between keys that are intended to be used as
      the secure entry point into the zone when building chains of
      trust, i.e., they are (to be) pointed to by parental DS RRs or
      configured as a trust anchor....  Therefore, it is suggested that
      the SEP flag be set on keys that are used as KSKs and not on keys
      that are used as ZSKs, while in those cases where a distinction
      between a KSK and ZSK is not made (i.e., for a Single-Type Signing
      Scheme), it is suggested that the SEP flag be set on all keys."
      (Quoted from [RFC6781], Section 3.2.3) Note that the SEP flag is
      only a hint, and its presence or absence may not be used to
      disqualify a given DNSKEY RR from use as a KSK or ZSK during
   Secure Entry Point (SEP):  A flag in the DNSKEY RDATA that "can be
      used to distinguish between keys that are intended to be used as
      the secure entry point into the zone when building chains of
      trust, i.e., they are (to be) pointed to by parental DS RRs or
      configured as a trust anchor....  Therefore, it is suggested that
      the SEP flag be set on keys that are used as KSKs and not on keys
      that are used as ZSKs, while in those cases where a distinction
      between a KSK and ZSK is not made (i.e., for a Single-Type Signing
      Scheme), it is suggested that the SEP flag be set on all keys."
      (Quoted from [RFC6781], Section 3.2.3) Note that the SEP flag is
      only a hint, and its presence or absence may not be used to
      disqualify a given DNSKEY RR from use as a KSK or ZSK during

The original definition of SEPs was in [RFC3757]. That definition clearly indicated that the SEP was a key, not just a bit in the key. The abstract of [RFC3757] says: "With the Delegation Signer (DS) resource record (RR), the concept of a public key acting as a secure entry point (SEP) has been introduced. During exchanges of public keys with the parent there is a need to differentiate SEP keys from other public keys in the Domain Name System KEY (DNSKEY) resource record set. A flag bit in the DNSKEY RR is defined to

SEP的原始定义见[RFC3757]。这一定义清楚地表明,SEP是一个关键,而不仅仅是关键中的一点。[RFC3757]的摘要说:“通过委托签名者(DS)资源记录(RR),引入了公钥作为安全入口点(SEP)的概念。在与父代交换公钥时,需要将SEP密钥与域名系统密钥(DNSKEY)中的其他公钥区分开来资源记录集。DNSKEY RR中的标志位定义为

indicate that DNSKEY is to be used as a SEP." That definition of the SEP as a key was made obsolete by [RFC4034], and the definition from [RFC6781] is consistent with [RFC4034].


Trust anchor: "A configured DNSKEY RR or DS RR hash of a DNSKEY RR. A validating security-aware resolver uses this public key or hash as a starting point for building the authentication chain to a signed DNS response. In general, a validating resolver will have to obtain the initial values of its trust anchors via some secure or trusted means outside the DNS protocol." (Quoted from [RFC4033], Section 2)

信任锚:“DNSKEY RR的已配置DNSKEY RR或DS RR哈希。具有验证安全意识的解析器使用此公钥或哈希作为起点,以构建签名DNS响应的身份验证链。一般来说,验证解析程序必须通过DNS协议之外的安全或可信方式获得其信任锚的初始值。”(引自[RFC4033],第2节)

DNSSEC Policy (DP): A statement that "sets forth the security requirements and standards to be implemented for a DNSSEC-signed zone." (Quoted from [RFC6841], Section 2)


DNSSEC Practice Statement (DPS): "A practices disclosure document that may support and be a supplemental document to the DNSSEC Policy (if such exists), and it states how the management of a given zone implements procedures and controls at a high level." (Quoted from [RFC6841], Section 2)


Hardware security module (HSM): A specialized piece of hardware that is used to create keys for signatures and to sign messages without ever disclosing the private key. In DNSSEC, HSMs are often used to hold the private keys for KSKs and ZSKs and to create the signatures used in RRSIG records at periodic intervals.


Signing software: Authoritative DNS servers that support DNSSEC often contain software that facilitates the creation and maintenance of DNSSEC signatures in zones. There is also stand-alone software that can be used to sign a zone regardless of whether the authoritative server itself supports signing. Sometimes signing software can support particular HSMs as part of the signing process.


11. DNSSEC States

A validating resolver can determine that a response is in one of four states: secure, insecure, bogus, or indeterminate. These states are defined in [RFC4033] and [RFC4035], although the definitions in the two documents differ a bit. This document makes no effort to reconcile the definitions in the two documents, and takes no position as to whether they need to be reconciled.


Section 5 of [RFC4033] says:


A validating resolver can determine the following 4 states:


Secure: The validating resolver has a trust anchor, has a chain of trust, and is able to verify all the signatures in the response.


Insecure: The validating resolver has a trust anchor, a chain of trust, and, at some delegation point, signed proof of the non-existence of a DS record. This indicates that subsequent branches in the tree are provably insecure. A validating resolver may have a local policy to mark parts of the domain space as insecure.


Bogus: The validating resolver has a trust anchor and a secure delegation indicating that subsidiary data is signed, but the response fails to validate for some reason: missing signatures, expired signatures, signatures with unsupported algorithms, data missing that the relevant NSEC RR says should be present, and so forth.

伪造:验证解析程序有一个信任锚点和一个安全委托,指示子数据已签名,但由于某些原因,响应无法验证:签名缺失、签名过期、算法不受支持的签名、相关NSEC RR表示应该存在的数据缺失,等等。

Indeterminate: There is no trust anchor that would indicate that a specific portion of the tree is secure. This is the default operation mode.


Section 4.3 of [RFC4035] says:


A security-aware resolver must be able to distinguish between four cases:


Secure: An RRset for which the resolver is able to build a chain of signed DNSKEY and DS RRs from a trusted security anchor to the RRset. In this case, the RRset should be signed and is subject to signature validation, as described above.

安全:解析程序能够为其构建从受信任安全锚到RRset的签名DNSKEY和DS RRs链的RRset。在这种情况下,如上所述,RRset应该被签名并接受签名验证。

Insecure: An RRset for which the resolver knows that it has no chain of signed DNSKEY and DS RRs from any trusted starting point to the RRset. This can occur when the target RRset lies in an unsigned zone or in a descendent [sic] of an unsigned zone. In this case, the RRset may or may not be signed, but the resolver will not be able to verify the signature.

不安全:冲突解决程序知道它没有从任何可信起点到RRset的签名DNSKEY和DS RRs链的RRset。当目标RRset位于无符号区域或无符号区域的后代[sic]中时,可能会发生这种情况。在这种情况下,RRset可能会被签名,也可能不会被签名,但解析器将无法验证签名。

Bogus: An RRset for which the resolver believes that it ought to be able to establish a chain of trust but for which it is unable to do so, either due to signatures that for some reason fail to validate or due to missing data that the relevant DNSSEC RRs indicate should be present. This case may indicate

伪造:一种RRset,解析程序认为它应该能够为其建立信任链,但由于签名由于某种原因无法验证,或者由于相关DNSSEC RRs指示应存在的数据缺失,它无法建立信任链。这种情况可能表明

an attack but may also indicate a configuration error or some form of data corruption.


Indeterminate: An RRset for which the resolver is not able to determine whether the RRset should be signed, as the resolver is not able to obtain the necessary DNSSEC RRs. This can occur when the security-aware resolver is not able to contact security-aware name servers for the relevant zones.

不确定:由于解析程序无法获得必要的DNSSEC RRs,因此解析程序无法确定是否应对其进行签名的RRset。当安全感知解析器无法联系相关区域的安全感知名称服务器时,可能会发生这种情况。

12. Security Considerations
12. 安全考虑

These definitions do not change any security considerations for the DNS.


13. IANA Considerations
13. IANA考虑

This document has no IANA actions.


14. References
14. 工具书类
14.1. Normative References
14.1. 规范性引用文件

[IANA_RootFiles] IANA, "Root Files", <>.


[RFC0882] Mockapetris, P., "Domain names: Concepts and facilities", RFC 882, DOI 10.17487/RFC0882, November 1983, <>.

[RFC0882]Mockapetris,P.,“域名:概念和设施”,RFC 882,DOI 10.17487/RFC0882,1983年11月<>.

[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, <>.

[RFC1034]Mockapetris,P.,“域名-概念和设施”,STD 13,RFC 1034,DOI 10.17487/RFC1034,1987年11月<>.

[RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, November 1987, <>.

[RFC1035]Mockapetris,P.,“域名-实现和规范”,STD 13,RFC 1035,DOI 10.17487/RFC1035,1987年11月<>.

[RFC1123] Braden, R., Ed., "Requirements for Internet Hosts - Application and Support", STD 3, RFC 1123, DOI 10.17487/RFC1123, October 1989, <>.

[RFC1123]Braden,R.,Ed.“互联网主机的要求-应用和支持”,STD 3,RFC 1123,DOI 10.17487/RFC1123,1989年10月<>.

[RFC1912] Barr, D., "Common DNS Operational and Configuration Errors", RFC 1912, DOI 10.17487/RFC1912, February 1996, <>.

[RFC1912]Barr,D.,“常见DNS操作和配置错误”,RFC 1912,DOI 10.17487/RFC1912,1996年2月<>.

[RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)", RFC 1996, DOI 10.17487/RFC1996, August 1996, <>.

[RFC1996]Vixie,P.,“区域变更即时通知机制(DNS通知)”,RFC 1996,DOI 10.17487/RFC1996,1996年8月<>.

[RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, "Dynamic Updates in the Domain Name System (DNS UPDATE)", RFC 2136, DOI 10.17487/RFC2136, April 1997, <>.

[RFC2136]Vixie,P.,Ed.,Thomson,S.,Rekhter,Y.,和J.Bound,“域名系统中的动态更新(DNS更新)”,RFC 2136,DOI 10.17487/RFC2136,1997年4月<>.

[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997, <>.

[RFC2181]Elz,R.和R.Bush,“DNS规范的澄清”,RFC 2181,DOI 10.17487/RFC2181,1997年7月<>.

[RFC2182] Elz, R., Bush, R., Bradner, S., and M. Patton, "Selection and Operation of Secondary DNS Servers", BCP 16, RFC 2182, DOI 10.17487/RFC2182, July 1997, <>.

[RFC2182]Elz,R.,Bush,R.,Bradner,S.,和M.Patton,“辅助DNS服务器的选择和操作”,BCP 16,RFC 2182,DOI 10.17487/RFC2182,1997年7月<>.

[RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS NCACHE)", RFC 2308, DOI 10.17487/RFC2308, March 1998, <>.

[RFC2308]Andrews,M.“DNS查询的反向缓存(DNS NCACHE)”,RFC 2308,DOI 10.17487/RFC2308,1998年3月<>.

[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, DOI 10.17487/RFC4033, March 2005, <>.

[RFC4033]Arends,R.,Austein,R.,Larson,M.,Massey,D.,和S.Rose,“DNS安全介绍和要求”,RFC 4033,DOI 10.17487/RFC4033,2005年3月<>.

[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, DOI 10.17487/RFC4034, March 2005, <>.

[RFC4034]Arends,R.,Austein,R.,Larson,M.,Massey,D.,和S.Rose,“DNS安全扩展的资源记录”,RFC 4034,DOI 10.17487/RFC4034,2005年3月<>.

[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005, <>.

[RFC4035]Arends,R.,Austein,R.,Larson,M.,Massey,D.,和S.Rose,“DNS安全扩展的协议修改”,RFC 4035,DOI 10.17487/RFC4035,2005年3月<>.

[RFC4592] Lewis, E., "The Role of Wildcards in the Domain Name System", RFC 4592, DOI 10.17487/RFC4592, July 2006, <>.

[RFC4592]Lewis,E.,“通配符在域名系统中的作用”,RFC 4592,DOI 10.17487/RFC4592,2006年7月<>.

[RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS Security (DNSSEC) Hashed Authenticated Denial of Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008, <>.

[RFC5155]Laurie,B.,Sisson,G.,Arends,R.,和D.Blacka,“DNS安全(DNSSEC)哈希认证拒绝存在”,RFC 5155,DOI 10.17487/RFC5155,2008年3月<>.

[RFC5358] Damas, J. and F. Neves, "Preventing Use of Recursive Nameservers in Reflector Attacks", BCP 140, RFC 5358, DOI 10.17487/RFC5358, October 2008, <>.

[RFC5358]Damas,J.和F.Neves,“防止在反射器攻击中使用递归名称服务器”,BCP 140,RFC 5358,DOI 10.17487/RFC5358,2008年10月<>.

[RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)", STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009, <>.

[RFC5730]Hollenbeck,S.,“可扩展资源调配协议(EPP)”,STD 69,RFC 5730,DOI 10.17487/RFC5730,2009年8月<>.

[RFC5731] Hollenbeck, S., "Extensible Provisioning Protocol (EPP) Domain Name Mapping", STD 69, RFC 5731, DOI 10.17487/RFC5731, August 2009, <>.

[RFC5731]Hollenbeck,S.,“可扩展资源调配协议(EPP)域名映射”,STD 69,RFC 5731,DOI 10.17487/RFC5731,2009年8月<>.

[RFC5855] Abley, J. and T. Manderson, "Nameservers for IPv4 and IPv6 Reverse Zones", BCP 155, RFC 5855, DOI 10.17487/RFC5855, May 2010, <>.

[RFC5855]Abley,J.和T.Manderson,“IPv4和IPv6反向区域的名称服务器”,BCP 155,RFC 5855,DOI 10.17487/RFC5855,2010年5月<>.

[RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010, <>.

[RFC5936]Lewis,E.and A.Hoenes,Ed.,“DNS区域传输协议(AXFR)”,RFC 5936,DOI 10.17487/RFC5936,2010年6月<>.

[RFC6561] Livingood, J., Mody, N., and M. O'Reirdan, "Recommendations for the Remediation of Bots in ISP Networks", RFC 6561, DOI 10.17487/RFC6561, March 2012, <>.

[RFC6561]Livingood,J.,Mody,N.,和M.O'Reirdan,“ISP网络中机器人修复的建议”,RFC 6561,DOI 10.17487/RFC65612012年3月<>.

[RFC6781] Kolkman, O., Mekking, W., and R. Gieben, "DNSSEC Operational Practices, Version 2", RFC 6781, DOI 10.17487/RFC6781, December 2012, <>.

[RFC6781]Kolkman,O.,Mekking,W.和R.Gieben,“DNSSEC操作规程,第2版”,RFC 6781,DOI 10.17487/RFC6781,2012年12月<>.

[RFC6840] Weiler, S., Ed. and D. Blacka, Ed., "Clarifications and Implementation Notes for DNS Security (DNSSEC)", RFC 6840, DOI 10.17487/RFC6840, February 2013, <>.

[RFC6840]Weiler,S.,Ed.和D.Blacka,Ed.,“DNS安全性(DNSSEC)的澄清和实施说明”,RFC 6840,DOI 10.17487/RFC6840,2013年2月<>.

[RFC6841] Ljunggren, F., Eklund Lowinder, AM., and T. Okubo, "A Framework for DNSSEC Policies and DNSSEC Practice Statements", RFC 6841, DOI 10.17487/RFC6841, January 2013, <>.

[RFC6841]Ljunggren,F.,Eklund Lowinder,AM.,和T.Okubo,“DNSSEC政策和DNSSEC实践声明框架”,RFC 6841,DOI 10.17487/RFC6841,2013年1月<>.

[RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms for DNS (EDNS(0))", STD 75, RFC 6891, DOI 10.17487/RFC6891, April 2013, <>.

[RFC6891]Damas,J.,Graff,M.,和P.Vixie,“DNS的扩展机制(EDNS(0)),STD 75,RFC 6891,DOI 10.17487/RFC68911913年4月<>.

[RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating DNSSEC Delegation Trust Maintenance", RFC 7344, DOI 10.17487/RFC7344, September 2014, <>.

[RFC7344]Kumari,W.,Gudmundsson,O.,和G.Barwood,“自动化DNSSEC委托信托维护”,RFC 7344,DOI 10.17487/RFC73442014年9月<>.

[RFC7719] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS Terminology", RFC 7719, DOI 10.17487/RFC7719, December 2015, <>.

[RFC7719]Hoffman,P.,Sullivan,A.和K.Fujiwara,“DNS术语”,RFC 7719,DOI 10.17487/RFC77192015年12月<>.

[RFC8310] Dickinson, S., Gillmor, D., and T. Reddy, "Usage Profiles for DNS over TLS and DNS over DTLS", RFC 8310, DOI 10.17487/RFC8310, March 2018, <>.

[RFC8310]Dickinson,S.,Gillmor,D.,和T.Reddy,“通过TLS的DNS和通过DTL的DNS的使用概况”,RFC 8310,DOI 10.17487/RFC8310,2018年3月<>.

14.2. Informative References
14.2. 资料性引用

[IANA_Resource_Registry] IANA, "Resource Record (RR) TYPEs", <>.


[RFC819] Su, Z. and J. Postel, "The Domain Naming Convention for Internet User Applications", RFC 819, DOI 10.17487/RFC0819, August 1982, <>.

[RFC819]Su,Z.和J.Postel,“互联网用户应用程序的域命名约定”,RFC 819,DOI 10.17487/RFC0819,1982年8月<>.

[RFC952] Harrenstien, K., Stahl, M., and E. Feinler, "DoD Internet host table specification", RFC 952, DOI 10.17487/RFC0952, October 1985, <>.

[RFC952]Harrenstien,K.,Stahl,M.和E.Feinler,“国防部互联网主机表规范”,RFC 952,DOI 10.17487/RFC0952,1985年10月<>.

[RFC1713] Romao, A., "Tools for DNS debugging", FYI 27, RFC 1713, DOI 10.17487/RFC1713, November 1994, <>.

[RFC1713]Romao,A.,“DNS调试工具”,FYI 27,RFC 1713,DOI 10.17487/RFC1713,1994年11月<>.

[RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, DOI 10.17487/RFC1995, August 1996, <>.

[RFC1995]Ohta,M.,“DNS中的增量区域转移”,RFC 1995,DOI 10.17487/RFC1995,1996年8月<>.

[RFC2775] Carpenter, B., "Internet Transparency", RFC 2775, DOI 10.17487/RFC2775, February 2000, <>.

[RFC2775]Carpenter,B.,“互联网透明度”,RFC 2775,DOI 10.17487/RFC2775,2000年2月<>.

[RFC3172] Huston, G., Ed., "Management Guidelines & Operational Requirements for the Address and Routing Parameter Area Domain ("arpa")", BCP 52, RFC 3172, DOI 10.17487/RFC3172, September 2001, <>.

[RFC3172]Huston,G.,Ed.“地址和路由参数区域域(“arpa”)的管理指南和操作要求”,BCP 52,RFC 3172,DOI 10.17487/RFC3172,2001年9月<>.

[RFC3425] Lawrence, D., "Obsoleting IQUERY", RFC 3425, DOI 10.17487/RFC3425, November 2002, <>.

[RFC3425]Lawrence,D.,“淘汰液体”,RFC 3425DOI 10.17487/RFC3425,2002年11月<>.

[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W. Stevens, "Basic Socket Interface Extensions for IPv6", RFC 3493, DOI 10.17487/RFC3493, February 2003, <>.

[RFC3493]Gilligan,R.,Thomson,S.,Bound,J.,McCann,J.,和W.Stevens,“IPv6的基本套接字接口扩展”,RFC 3493,DOI 10.17487/RFC3493,2003年2月<>.

[RFC3757] Kolkman, O., Schlyter, J., and E. Lewis, "Domain Name System KEY (DNSKEY) Resource Record (RR) Secure Entry Point (SEP) Flag", RFC 3757, DOI 10.17487/RFC3757, April 2004, <>.

[RFC3757]Kolkman,O.,Schlyter,J.,和E.Lewis,“域名系统密钥(DNSKEY)资源记录(RR)安全入口点(SEP)标志”,RFC 3757,DOI 10.17487/RFC3757,2004年4月<>.

[RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912, DOI 10.17487/RFC3912, September 2004, <>.

[RFC3912]Daigle,L.,“WHOIS协议规范”,RFC 3912,DOI 10.17487/RFC3912,2004年9月<>.

[RFC4641] Kolkman, O. and R. Gieben, "DNSSEC Operational Practices", RFC 4641, DOI 10.17487/RFC4641, September 2006, <>.

[RFC4641]Kolkman,O.和R.Gieben,“DNSSEC运营实践”,RFC 4641,DOI 10.17487/RFC46412006年9月<>.

[RFC4697] Larson, M. and P. Barber, "Observed DNS Resolution Misbehavior", BCP 123, RFC 4697, DOI 10.17487/RFC4697, October 2006, <>.

[RFC4697]Larson,M.和P.Barber,“观察到的DNS解析错误行为”,BCP 123,RFC 4697,DOI 10.17487/RFC4697,2006年10月<>.

[RFC4786] Abley, J. and K. Lindqvist, "Operation of Anycast Services", BCP 126, RFC 4786, DOI 10.17487/RFC4786, December 2006, <>.

[RFC4786]Abley,J.和K.Lindqvist,“任意广播服务的运营”,BCP 126,RFC 4786,DOI 10.17487/RFC4786,2006年12月<>.

[RFC4956] Arends, R., Kosters, M., and D. Blacka, "DNS Security (DNSSEC) Opt-In", RFC 4956, DOI 10.17487/RFC4956, July 2007, <>.

[RFC4956]Arends,R.,Kosters,M.,和D.Blacka,“DNS安全(DNSSEC)选择加入”,RFC 4956,DOI 10.17487/RFC4956,2007年7月<>.

[RFC5625] Bellis, R., "DNS Proxy Implementation Guidelines", BCP 152, RFC 5625, DOI 10.17487/RFC5625, August 2009, <>.

[RFC5625]Bellis,R.,“DNS代理实施指南”,BCP 152,RFC 5625,DOI 10.17487/RFC5625,2009年8月<>.

[RFC5890] Klensin, J., "Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework", RFC 5890, DOI 10.17487/RFC5890, August 2010, <>.

[RFC5890]Klensin,J.,“应用程序的国际化域名(IDNA):定义和文档框架”,RFC 5890,DOI 10.17487/RFC5890,2010年8月<>.

[RFC5891] Klensin, J., "Internationalized Domain Names in Applications (IDNA): Protocol", RFC 5891, DOI 10.17487/RFC5891, August 2010, <>.

[RFC5891]Klensin,J.,“应用程序中的国际化域名(IDNA):协议”,RFC 5891,DOI 10.17487/RFC5891,2010年8月<>.

[RFC5892] Faltstrom, P., Ed., "The Unicode Code Points and Internationalized Domain Names for Applications (IDNA)", RFC 5892, DOI 10.17487/RFC5892, August 2010, <>.

[RFC5892]Faltstrom,P.,Ed.“Unicode码点和应用程序的国际化域名(IDNA)”,RFC 5892,DOI 10.17487/RFC5892,2010年8月<>.

[RFC5893] Alvestrand, H., Ed. and C. Karp, "Right-to-Left Scripts for Internationalized Domain Names for Applications (IDNA)", RFC 5893, DOI 10.17487/RFC5893, August 2010, <>.

[RFC5893]Alvestrand,H.,Ed.和C.Karp,“应用程序国际化域名(IDNA)的从右到左脚本”,RFC 5893,DOI 10.17487/RFC5893,2010年8月<>.

[RFC5894] Klensin, J., "Internationalized Domain Names for Applications (IDNA): Background, Explanation, and Rationale", RFC 5894, DOI 10.17487/RFC5894, August 2010, <>.

[RFC5894]Klensin,J.,“应用程序的国际化域名(IDNA):背景、解释和理由”,RFC 5894,DOI 10.17487/RFC5894,2010年8月<>.

[RFC6055] Thaler, D., Klensin, J., and S. Cheshire, "IAB Thoughts on Encodings for Internationalized Domain Names", RFC 6055, DOI 10.17487/RFC6055, February 2011, <>.

[RFC6055]Thaler,D.,Klensin,J.,和S.Cheshire,“IAB对国际化域名编码的思考”,RFC 6055,DOI 10.17487/RFC6055,2011年2月<>.

[RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, DOI 10.17487/RFC6265, April 2011, <>.

[RFC6265]Barth,A.,“HTTP状态管理机制”,RFC 6265,DOI 10.17487/RFC6265,2011年4月<>.

[RFC6303] Andrews, M., "Locally Served DNS Zones", BCP 163, RFC 6303, DOI 10.17487/RFC6303, July 2011, <>.

[RFC6303]Andrews,M.,“本地服务DNS区域”,BCP 163,RFC 6303,DOI 10.17487/RFC6303,2011年7月<>.

[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. Cheshire, "Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry", BCP 165, RFC 6335, DOI 10.17487/RFC6335, August 2011, <>.

[RFC6335]Cotton,M.,Eggert,L.,Touch,J.,Westerlund,M.,和S.Cheshire,“互联网分配号码管理局(IANA)服务名称和传输协议端口号注册管理程序”,BCP 165,RFC 6335,DOI 10.17487/RFC6335,2011年8月<>.

[RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in Internationalization in the IETF", BCP 166, RFC 6365, DOI 10.17487/RFC6365, September 2011, <>.

[RFC6365]Hoffman,P.和J.Klensin,“IETF国际化中使用的术语”,BCP 166,RFC 6365,DOI 10.17487/RFC6365,2011年9月<>.

[RFC6672] Rose, S. and W. Wijngaards, "DNAME Redirection in the DNS", RFC 6672, DOI 10.17487/RFC6672, June 2012, <>.

[RFC6672]Rose,S.和W.Wijngaards,“DNS中的DNAME重定向”,RFC 6672,DOI 10.17487/RFC6672,2012年6月<>.

[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, DOI 10.17487/RFC6762, February 2013, <>.

[RFC6762]Cheshire,S.和M.Krochmal,“多播DNS”,RFC 6762,DOI 10.17487/RFC6762,2013年2月<>.

[RFC7129] Gieben, R. and W. Mekking, "Authenticated Denial of Existence in the DNS", RFC 7129, DOI 10.17487/RFC7129, February 2014, <>.

[RFC7129]Gieben,R.和W.Mekking,“DNS中的认证拒绝存在”,RFC 7129,DOI 10.17487/RFC7129,2014年2月<>.

[RFC7480] Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the Registration Data Access Protocol (RDAP)", RFC 7480, DOI 10.17487/RFC7480, March 2015, <>.

[RFC7480]Newton,A.,Ellacott,B.,和N.Kong,“注册数据访问协议(RDAP)中的HTTP使用”,RFC 7480,DOI 10.17487/RFC7480,2015年3月<>.

[RFC7481] Hollenbeck, S. and N. Kong, "Security Services for the Registration Data Access Protocol (RDAP)", RFC 7481, DOI 10.17487/RFC7481, March 2015, <>.

[RFC7481]Hollenbeck,S.和N.Kong,“注册数据访问协议(RDAP)的安全服务”,RFC 7481,DOI 10.17487/RFC7481,2015年3月<>.

[RFC7482] Newton, A. and S. Hollenbeck, "Registration Data Access Protocol (RDAP) Query Format", RFC 7482, DOI 10.17487/RFC7482, March 2015, <>.

[RFC7482]Newton,A.和S.Hollenbeck,“注册数据访问协议(RDAP)查询格式”,RFC 7482,DOI 10.17487/RFC7482,2015年3月<>.

[RFC7483] Newton, A. and S. Hollenbeck, "JSON Responses for the Registration Data Access Protocol (RDAP)", RFC 7483, DOI 10.17487/RFC7483, March 2015, <>.

[RFC7483]Newton,A.和S.Hollenbeck,“注册数据访问协议(RDAP)的JSON响应”,RFC 7483,DOI 10.17487/RFC7483,2015年3月<>.

[RFC7484] Blanchet, M., "Finding the Authoritative Registration Data (RDAP) Service", RFC 7484, DOI 10.17487/RFC7484, March 2015, <>.

[RFC7484]Blanchet,M.“查找权威注册数据(RDAP)服务”,RFC 7484,DOI 10.17487/RFC7484,2015年3月<>.

[RFC7485] Zhou, L., Kong, N., Shen, S., Sheng, S., and A. Servin, "Inventory and Analysis of WHOIS Registration Objects", RFC 7485, DOI 10.17487/RFC7485, March 2015, <>.

[RFC7485]Zhou,L.,Kong,N.,Shen,S.,Sheng,S.,和A.Servin,“WHOIS登记对象的清查和分析”,RFC 7485,DOI 10.17487/RFC7485,2015年3月<>.

[RFC7793] Andrews, M., "Adding Prefixes to the IPv4 Locally-Served DNS Zones Registry", BCP 163, RFC 7793, DOI 10.17487/RFC7793, May 2016, <>.

[RFC7793]Andrews,M.,“向IPv4本地服务DNS区域注册表添加100.64.0.0/10前缀”,BCP 163,RFC 7793,DOI 10.17487/RFC7793,2016年5月<>.

[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., and P. Hoffman, "Specification for DNS over Transport Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 2016, <>.

[RFC7858]Hu,Z.,Zhu,L.,Heidemann,J.,Mankin,A.,Wessels,D.,和P.Hoffman,“DNS传输层安全规范(TLS)”,RFC 7858,DOI 10.17487/RFC7858,2016年5月<>.

[RFC8094] Reddy, T., Wing, D., and P. Patil, "DNS over Datagram Transport Layer Security (DTLS)", RFC 8094, DOI 10.17487/RFC8094, February 2017, <>.

[RFC8094]Reddy,T.,Wing,D.,和P.Patil,“数据报传输层安全(DTLS)上的DNS”,RFC 8094,DOI 10.17487/RFC8094,2017年2月<>.

[RFC8109] Koch, P., Larson, M., and P. Hoffman, "Initializing a DNS Resolver with Priming Queries", BCP 209, RFC 8109, DOI 10.17487/RFC8109, March 2017, <>.

[RFC8109]Koch,P.,Larson,M.,和P.Hoffman,“使用启动查询初始化DNS解析程序”,BCP 209,RFC 8109,DOI 10.17487/RFC8109,2017年3月<>.

[RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, <>.

[RFC8484]Hoffman,P.和P.McManus,“HTTPS(DoH)上的DNS查询”,RFC 8484,DOI 10.17487/RFC8484,2018年10月<>.

[RSSAC026] Root Server System Advisory Committee (RSSAC), "RSSAC Lexicon", 2017, < rssac-026-14mar17-en.pdf>.

[RSSAC026]根服务器系统咨询委员会(RSSAC),“RSSAC词典”,2017年< rssac-026-14mar17-en.pdf>。

Appendix A. Definitions Updated by This Document

The following definitions from RFCs are updated by this document:


o Forwarder in [RFC2308]

o [RFC2308]中的货运代理

o QNAME in [RFC2308]

o [RFC2308]中的QNAME

o Secure Entry Point (SEP) in [RFC3757]; note, however, that this RFC is already obsolete (see [RFC4033], [RFC4034], [RFC4035]).

o [RFC3757]中的安全入口点(SEP);但是,请注意,此RFC已经过时(请参阅[RFC4033]、[RFC4034]、[RFC4035])。

Appendix B. Definitions First Defined in This Document

The following definitions are first defined in this document:


o "Alias" in Section 2

o 第2节中的“别名”

o "Apex" in Section 7

o 第7节中的“顶点”

o "arpa" in Section 7

o 第7节中的“arpa”

o "Bailiwick" in Section 7

o 第7条中的“辖区”

o "Class independent" in Section 5

o 第5节中的“阶级独立”

o "Delegation-centric zone" in Section 7

o 第7节中的“委托中心区”

o "Delegation" in Section 7

o 第7节中的“授权”

o "DNS operator" in Section 9

o 第9节中的“DNS操作员”

o "DNSSEC-aware" in Section 10

o 第10节中的“DNSSEC意识”

o "DNSSEC-unaware" in Section 10

o 第10节中的“DNSSEC未意识到”

o "Forwarding" in Section 6

o 第6节中的“转发”

o "Full resolver" in Section 6

o 第6节中的“完全分解器”

o "Fully-qualified domain name" in Section 2

o 第2节中的“完全限定域名”

o "Global DNS" in Section 2

o 第2节中的“全局DNS”

o "Hardware Security Module (HSM)" in Section 10

o 第10节中的“硬件安全模块(HSM)”

o "Host name" in Section 2

o 第2节中的“主机名”

o "IDN" in Section 2

o 第2节中的“IDN”

o "In-bailiwick" in Section 7

o 第7条中的“辖区内”

o "Iterative resolution" in Section 6

o 第6节中的“迭代解决方案”

o "Label" in Section 2

o 第2节中的“标签”

o "Locally served DNS zone" in Section 2

o 第2节中的“本地服务DNS区域”

o "Naming system" in Section 2

o 第2节中的“命名系统”

o "Negative response" in Section 3

o 第3节中的“否定回答”

o "Non-recursive query" in Section 6

o 第6节中的“非递归查询”

o "Open resolver" in Section 6

o 第6节中的“开放式分解器”

o "Out-of-bailiwick" in Section 7

o 第7条中的“辖区外”

o "Passive DNS" in Section 6

o 第6节中的“被动DNS”

o "Policy-implementing resolver" in Section 6

o 第6节中的“策略执行解析器”

o "Presentation format" in Section 5

o 第5节中的“演示文稿格式”

o "Priming" in Section 6

o 第6节中的“启动”

o "Private DNS" in Section 2

o 第2节中的“专用DNS”

o "Recursive resolver" in Section 6

o 第6节中的“递归解析器”

o "Referrals" in Section 4

o 第4节中的“转介”

o "Registrant" in Section 9

o 第9节中的“注册人”

o "Registrar" in Section 9

o 第9条中的“注册官”

o "Registry" in Section 9

o 第9条中的“注册处”

o "Root zone" in Section 7

o 第7节中的“根区”

o "Secure Entry Point (SEP)" in Section 10

o 第10节中的“安全入口点(SEP)”

o "Signing software" in Section 10

o 第10节中的“签名软件”

o "Split DNS" in Section 6

o 第6节中的“拆分DNS”

o "Stub resolver" in Section 6

o 第6节中的“存根解析器”

o "Subordinate" in Section 8

o 第8节中的“下属”

o "Superordinate" in Section 8

o 第8节中的“上级”

o "TLD" in Section 2

o 第2节中的“TLD”

o "Validating resolver" in Section 10

o 第10节中的“验证解析器”

o "Validation" in Section 10

o 第10节中的“验证”

o "View" in Section 6

o 第6节中的“视图”

o "Zone transfer" in Section 6

o 第6节中的“区域转移”



A Address records 16 Alias 9 Anycast 22 Apex 23 Asterisk label 27 Authoritative data 24 Authoritative server 19 Authoritative-only server 19 arpa: Address and Routing Parameter Area Domain 26

地址记录16别名9选播22顶点23星号标签27权威数据24权威服务器19仅权威服务器19 arpa:地址和路由参数区域域26

C CNAME 10 Canonical name 9 Child 22 Class 11 Class independent 16 Closest encloser 27 Closest provable encloser 27 Combined signing key (CSK) 33

C CNAME 10规范名称9子22类11类独立16最近封闭器27最近可证明封闭器27组合签名密钥(CSK)33

D DNS operator 29 DNSSEC Policy (DP) 34 DNSSEC Practice Statement (DPS) 34 DNSSEC-aware and DNSSEC-unaware 30 Delegation 24 Delegation-centric zone 26 Domain name 5

D DNS运营商29 DNSSEC策略(DP)34 DNSSEC实践声明(DPS)34 DNSSEC感知和DNSSEC感知30委派24委派中心区域26域名5

E EDNS 14 EPP 28 Empty non-terminals (ENT) 26

E EDNS 14 EPP 28空非终端(ENT)26

F FORMERR 10 Fast flux DNS 26 Forward lookup 26 Forwarder 21 Forwarding 20 Full resolver 18 Full-service resolver 18 Fully-qualified domain name (FQDN) 8

F FORMERR 10 Fast flux DNS 26转发查找26转发21转发20完全解析程序18完全服务解析程序18完全限定域名(FQDN)8

G Global DNS 5 Glue records 24

G全球DNS 5胶水记录24

H Hardware security module (HSM) 34 Hidden master 20 Host name 8


I IDN 9 In-bailiwick 25 Insecure delegation 31 Instance 22 Internationalized Domain Name 9 Iterative mode 17 Iterative resolution 18

I IDN 9在辖区25不安全的委派31实例22国际化域名9迭代模式17迭代解析18

K Key signing key (KSK) 33


L Label 5 Lame delegation 24 Locally served DNS zone 8

L标签5 Lame授权24本地服务DNS区域8

M Master file 14 Master server 19 Multicast DNS 7 mDNS 7

M主文件14主服务器19多播DNS 7 mDNS 7

N NODATA 10 NOERROR 10 NOTIMP 10 NS 19 NSEC 31 NSEC3 31 NXDOMAIN 10 Naming system 4 Negative caching 19 Negative response 11 Next closer name 28 Non-recursive query 18

N NODATA 10 NOERROR 10 NOTIMP 10 NS 19 NSEC 31 NSEC3 31 NXDOMAIN 10命名系统4负缓存19负响应11下一个更近的名称28非递归查询18

O OPT 14 Occluded name 26 Open resolver 21 Opt-out 31 Origin 23 Out-of-bailiwick 25 Owner 15


P Parent 23 Passive DNS 22 Policy-implementing resolver 21 Presentation format 14 Primary master 20 Primary server 20 Priming 18 Privacy-enabling DNS server 22 Private DNS 7 Public suffix 29

P Parent 23被动DNS 22策略实现解析器21表示格式14主服务器20主服务器20启动18隐私启用DNS服务器22私有DNS 7公共后缀29



R RDAP 29 REFUSED 10 RR 14 RRset 14 Recursive mode 17 Recursive query 18 Recursive resolver 17 Referrals 13 Registrant 28

R RDAP 29拒绝10 RR 14 RRset 14递归模式17递归查询18递归解析器17转介13注册者28

Registrar 28 Registry 28 Resolver 16 Reverse DNS, reverse lookup 26 Root hints 18 Root zone 26


S SERVFAIL 10 SOA 14 SOA field names 14 Secondary server 19 Secure Entry Point (SEP) 33 Service name 27 Signed zone 30 Signing software 34 Slave server 19 Source of Synthesis 28 Split DNS 21 Split-horizon DNS 21 Stealth server 20 Stub resolver 17 Subdomain 9 Subordinate 29 Superordinate 29

S SERVFAIL 10 SOA 14 SOA字段名称14辅助服务器19安全入口点(SEP)33服务名称27签名区域30签名软件34从属服务器19合成源28拆分DNS 21拆分地平线DNS 21隐形服务器20存根解析程序17子域9从属29上级29

T TLD 9 TTL 15 Trust anchor 34

T TLD 9 TTL 15信任锚34

U Unsigned zone 30


V Validating resolver 33 Validation 32 View 21


W WHOIS 28 Wildcard 27 Wildcard domain name 27

W WHOIS 28通配符27通配符域名27

Z Zone 22 Zone cut 23 Zone enumeration 31 Zone signing key (ZSK) 33 Zone transfer 19




The following is the Acknowledgements section of RFC 7719.

以下是RFC 7719的确认部分。

The authors gratefully acknowledge all of the authors of DNS-related RFCs that proceed this one. Comments from Tony Finch, Stephane Bortzmeyer, Niall O'Reilly, Colm MacCarthaigh, Ray Bellis, John Kristoff, Robert Edmonds, Paul Wouters, Shumon Huque, Paul Ebersman, David Lawrence, Matthijs Mekking, Casey Deccio, Bob Harold, Ed Lewis, John Klensin, David Black, and many others in the DNSOP Working Group helped shape RFC 7719.

作者衷心感谢所有从事此项工作的DNS相关RFC的作者。Tony Finch、Stephane Bortzmeyer、Niall O'Reilly、Colm MacCarthaigh、Ray Bellis、John Kristoff、Robert Edmonds、Paul Wouters、Shumon Huque、Paul Ebersman、David Lawrence、Matthijs Mekking、Casey Deccio、Bob Harold、Ed Lewis、John Klesins、David Black和DNSOP工作组中的许多其他人的评论帮助形成了RFC 7719。

Most of the major changes between RFC 7719 and this document came from active discussion on the DNSOP WG. Specific people who contributed material to this document include: Bob Harold, Dick Franks, Evan Hunt, John Dickinson, Mark Andrews, Martin Hoffmann, Paul Vixie, Peter Koch, Duane Wessels, Allison Mankin, Giovane Moura, Roni Even, Dan Romascanu, and Vladmir Cunat.

RFC 7719和本文件之间的大部分主要变化来自DNSOP工作组的积极讨论。为本文件提供材料的具体人员包括:鲍勃·哈罗德、迪克·弗兰克斯、埃文·亨特、约翰·迪金森、马克·安德鲁斯、马丁·霍夫曼、保罗·维克西、彼得·科赫、杜安·韦塞尔、艾利森·曼金、乔万·莫拉、罗尼·埃文、丹·罗马斯坎努和弗拉德米尔·库纳特。

Authors' Addresses


Paul Hoffman ICANN



Andrew Sullivan



Kazunori Fujiwara Japan Registry Services Co., Ltd. Chiyoda First Bldg. East 13F, 3-8-1 Nishi-Kanda Chiyoda-ku, Tokyo 101-0065 Japan


   Phone: +81 3 5215 8451
   Phone: +81 3 5215 8451