Internet Engineering Task Force (IETF)                        P. Hoffman
Request for Comments: 7719                                         ICANN
Category: Informational                                      A. Sullivan
ISSN: 2070-1721                                                      Dyn
                                                             K. Fujiwara
                                                           December 2015
Internet Engineering Task Force (IETF)                        P. Hoffman
Request for Comments: 7719                                         ICANN
Category: Informational                                      A. Sullivan
ISSN: 2070-1721                                                      Dyn
                                                             K. Fujiwara
                                                           December 2015

DNS Terminology




The 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.


Status of This Memo


This document is not an Internet Standards Track specification; it is published for informational purposes.


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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.

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。并非IESG批准的所有文件都适用于任何级别的互联网标准;见RFC 5741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) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.

版权所有(c)2015 IETF信托基金和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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Names . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  DNS Header and Response Codes . . . . . . . . . . . . . . . .   6
   4.  Resource Records  . . . . . . . . . . . . . . . . . . . . . .   7
   5.  DNS Servers and Clients . . . . . . . . . . . . . . . . . . .   9
   6.  Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Registration Model  . . . . . . . . . . . . . . . . . . . . .  17
   8.  General DNSSEC  . . . . . . . . . . . . . . . . . . . . . . .  18
   9.  DNSSEC States . . . . . . . . . . . . . . . . . . . . . . . .  20
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  22
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  22
     11.2.  Informative References . . . . . . . . . . . . . . . . .  24
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  27
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  27
   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Names . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  DNS Header and Response Codes . . . . . . . . . . . . . . . .   6
   4.  Resource Records  . . . . . . . . . . . . . . . . . . . . . .   7
   5.  DNS Servers and Clients . . . . . . . . . . . . . . . . . . .   9
   6.  Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Registration Model  . . . . . . . . . . . . . . . . . . . . .  17
   8.  General DNSSEC  . . . . . . . . . . . . . . . . . . . . . . .  18
   9.  DNSSEC States . . . . . . . . . . . . . . . . . . . . . . . .  20
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  22
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  22
     11.2.  Informative References . . . . . . . . . . . . . . . . .  24
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  27
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  27
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. The protocol and message format are defined in [RFC1034] and [RFC1035]. These RFCs defined some terms, but later documents defined others. Some of the terms from RFCs 1034 and 1035 now have somewhat different meanings than they did in 1987.

域名系统(DNS)是一个简单的查询响应协议,其双向消息具有相同的格式。[RFC1034]和[RFC1035]中定义了协议和消息格式。这些RFC定义了一些术语,但后来的文档定义了其他术语。RFCs 1034和1035中的一些术语现在的含义与1987年有所不同。

This document collects a wide variety of DNS-related terms. Some of them have been precisely defined in earlier RFCs, some have been loosely defined in earlier RFCs, and some are not defined in any earlier RFC at all.


Most of the definitions here are 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.


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, the authors intend to follow this document with a substantial revision in the not-distant future. That revision will probably have more in-depth discussion of some terms as well as new terms; it will also update some of the RFCs with new definitions.

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,作者打算在不久的将来对本文件进行实质性修订。该修订可能会对某些术语以及新术语进行更深入的讨论;它还将用新的定义更新一些RFC。

The terms are organized loosely by topic. Some definitions are for new terms for things that are commonly talked about in the DNS community but that never had terms defined for them.


Other organizations sometimes define DNS-related terms their own way. For example, the W3C defines "domain" at


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.


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.


2. Names
2. 名字

Domain name: Section 3.1 of [RFC1034] talks of "the domain name space" as a tree structure. "Each node has a label, which is zero to 63 octets in length. ... The domain name of a node is the list of the labels on the path from the node to the root of the tree. ... To simplify implementations, the total number of octets that represent a domain name (i.e., the sum of all label octets and label lengths) is limited to 255." Any label in a domain name can contain any octet value.


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 final, 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 some of the right-most names are left off and are understood only by context.


Label: The identifier of an individual node in the sequence of nodes identified by a fully qualified domain name.


   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], the "preferred name syntax".  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
   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], the "preferred name syntax".  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

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".


TLD: A Top-Level Domain, meaning 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, 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.


IDN: The common abbreviation for "Internationalized Domain Name". The IDNA protocol is the standard mechanism for handling domain names with non-ASCII characters in applications in the DNS. The current standard, 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), and [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 "".


Alias: The owner of a CNAME resource record, or a subdomain of the owner of a DNAME resource record [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 is 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 an alias, not a canonical name." (Quoted from [RFC2181], Section 10.1.1)


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, and on which HTTP cookies ([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. At the time this document is published, the IETF DBOUND Working Group [DBOUND] is dealing with issues concerning public suffixes.

公共后缀:“由公共注册表控制的域。”(引自[RFC6265],第5.3节)该术语的常见定义是可以在其下注册子域,并且不应在其上设置HTTP cookies([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。在本文件发布时,IETF DBOUND工作组[DBOUND]正在处理与公共后缀有关的问题。

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 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 the case of the "uk" TLD around the time this document is published.


3. DNS Header and Response Codes
3. DNS头和响应代码

The header of a DNS message is its first 12 octets. Many of the fields and flags in the header diagram in Sections 4.1.1 through 4.1.3 of [RFC1035] are referred to by their names in that 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".


Some of response codes that are defined in [RFC1035] have gotten their own shorthand names. Some common response code names that appear without reference to the numeric value are "FORMERR", "SERVFAIL", and "NXDOMAIN" (the latter of which is also referred to as "Name Error"). All of the RCODEs are listed at, although that site uses mixed-case capitalization, while most documents use all-caps.

[RFC1035]中定义的一些响应代码有自己的简写名称。出现时未参考数值的一些常见响应代码名是“FORMERR”、“SERVFAIL”和“NXDOMAIN”(后者也称为“Name Error”)。所有RCODE都列在,尽管该网站使用大小写混合,而大多数文档使用全大写。

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 the nameserver cannot answer. Sections 2 and 7 of [RFC2308] describe the types of negative responses in detail.


Referrals: Data from the authority section of a non-authoritative answer. [RFC1035] Section 2.1 defines "authoritative" data. However, referrals at zone cuts (defined in Section 6) are not authoritative. Referrals may be zone cut NS resource records and their glue records. NS records on the parent side of a zone cut are an authoritative delegation, but are normally not treated as authoritative data. In general, a referral is a way for a server to send an answer saying that the server does not know the answer, but knows where the query should be directed in order to get an answer. Historically, many authoritative servers answered with a referral to the root zone when queried for a name for which they were not authoritative, but this practice has declined.


4. Resource Records
4. 资源记录

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


RRset: A set of resource records with the same label, class and type, but with different data. (Definition from [RFC2181]) Also spelled 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". (This definition is definitely not the same as "the response one gets to a query for QTYPE=ANY", which is an unfortunate misunderstanding.)


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 potentially 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 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。(定义见[RFC6891]第6.1.1节)EDN使用。

Owner: The domain name where a RR is found ([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. 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 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。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, the TTL is 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) Also: "the time interval (in seconds) that the resource record may be cached before it should be discarded". (Quoted from [RFC1035], Section 4.1.3). 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. Also, if a value is flushed from the cache when its value is still positive, the value effectively becomes zero. 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.

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。此外,如果某个值在其值仍然为正时从缓存中刷新,则该值实际上变为零。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。

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 classes other than IN (class 1, the Internet).


5. DNS Servers and Clients
5. 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.


Resolver: A program "that extract[s] information from name servers in response to client requests." (Quoted from [RFC1034], Section 2.4) "The resolver is located on the same machine as the program that requests the resolver's services, but it may need to consult name servers on other hosts." (Quoted from [RFC1034], Section 5.1) A resolver performs queries for a name, type, and class, and receives answers. 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.


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".


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". 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". While strictly the difference between these is that one of them sends queries to another recursive server and the other does not, 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.


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 mechanism used by a resolver to determine where to send queries before there is anything in the resolver's cache. Priming is most often done from a configuration setting that contains a list of authoritative servers for the root zone.


Negative caching: "The storage of knowledge that something does not exist, cannot give an answer, 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.) 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)


Zone transfer: The act of a client requesting a copy of a zone and an authoritative server sending the needed information. (See Section 6 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.


Secondary server: "An authoritative server which uses zone transfer to retrieve the zone" (Quoted from [RFC1996], Section 2.1). [RFC2182] describes secondary servers in 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". Secondary servers are also discussed in [RFC1034].

辅助服务器:“使用区域传输检索区域的权威服务器”(引用自[RFC1996]第2.1节)。[RFC2182]详细描述了辅助服务器。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”。[RFC1034]中还讨论了辅助服务器。

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

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”(引用自[RFC1996],第2.1节),或者更具体地说,“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”(引用自[RFC2136])。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”。[RFC1034]中还讨论了主服务器。

Master server: See primary server.


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." The idea of a primary master is only used by [RFC2136], and is considered archaic in other parts of the DNS.

主主机:“主主机在区域的SOA MNAME字段中命名,也可以由NS RR命名”。(引用自[RFC1996]第2.1节)。[RFC2136]将“主主机”定义为“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,也可以使用NS RR。根据定义,每个区域只有一个主主机服务器。“主主机的概念仅由[RFC2136]使用,在DNS的其他部分被认为是过时的。

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 master 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 be either a secondary or a primary master.

隐藏主机:作为区域传输主机的隐形服务器。“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。”(引用自[RFC6781],第3.4.3节)。早期的RFC[RFC4641]表示,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。隐藏主机可以是辅助主机或主主机。

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 need 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) stub resolver. 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.


View: A configuration for a DNS server that allows it to provide different answers depending on attributes of the query. 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 large amounts of DNS data by storing DNS responses from servers. Some of these systems also collect the DNS queries associated with the responses; this can raise privacy issues. Passive DNS databases can be used to answer historical questions about DNS zones such as which records were available for them at what times in the past. Passive DNS databases allow searching of the stored records on keys other than just the name, 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)


6. Zones
6. 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 [RFC882] as "the name server that has authority over the place in the domain name space that will hold the new domain". (Note that [RFC882] was obsoleted by [RFC1034] and [RFC1035].) [RFC819] also has some description of the relationship between parents and children.




(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)。分区名称与分区原点处的域名相同。”(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" as '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。

Glue records: "[Resource records] which are not part of the authoritative data [of the zone], and are address resource records 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." (Definition 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[子区域中的名称服务器]的地址资源记录。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。”无粘合“我们可能会遇到这样的情况: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联系服务器。”(定义见[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" ([RFC2181], Section 5.4.1). Although glue is sometimes used today with this wider definition in mind, the context surrounding the [RFC2181] definition suggests it is intended to apply to the use of glue within the document itself and not necessarily beyond.




(a) An adjective to describe a name server whose name is either subordinate to or (rarely) the same as the zone origin. In-bailiwick name servers require glue records in their parent zone (using the first of the definitions of "glue records" in the definition above).

(a) 描述名称服务器的形容词,其名称从属于或(很少)与区域来源相同。在辖区内,名称服务器需要在其父区域中使用粘合记录(使用上述定义中“粘合记录”的第一个定义)。

(b) Data for which the server is either authoritative, or else authoritative for an ancestor of the owner name. This sense of the term normally is used when discussing the relevancy of glue records in a response. For example, the server for the parent zone "" might reply with glue records for "". Because the "" zone is a descendant of the "" zone, the glue records are in-bailiwick.

(b) 服务器对其具有权威性或对所有者名称的祖先具有权威性的数据。这个术语的含义通常用于讨论响应中胶水记录的相关性。例如,父区域“”的服务器可能会使用“”的粘合记录进行回复。因为“”区域是“”区域的后代,所以粘合记录位于辖区内。

Out-of-bailiwick: The antonym of in-bailiwick.


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) It is noted that this definition might inadvertently also include any NS records that appear in the zone, even those that might not truly be authoritative because there are identical NS RRs below the zone cut. This reveals the ambiguity

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。”(引用[RFC1034],第4.2.1节)注意,该定义可能无意中还包括区域中出现的任何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。这就暴露了模糊性

in the notion of authoritative data, because the parent-side NS records authoritatively indicate the delegation, even though they are not themselves authoritative data.


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


Empty non-terminals: "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.

空的非终端:“没有资源记录但有子域的域名。”(引用[RFC4592],第2.2.2节)。一个典型的例子是SRV记录:在名称“”中,很可能“”没有RRset,但“”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 is not defined there.


Wildcard: [RFC1034] defined "wildcard", but in a way that turned out to be confusing to implementers. 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) For an extended discussion of wildcards, including clearer definitions, see [RFC4592].


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 typo corrected) It is often 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中发现一个域时,会使用多个IP地址的记录,每个IP地址都有一个非常短的生存时间(TTL)值。这意味着该域会在短时间内解析为不同的IP地址。(引用[RFC6561],第1.1.5节,并更正拼写错误)它经常被用来传送恶意软件。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。

7. Registration Model
7. 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 superior zones 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, or 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.


8. General DNSSEC

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.)


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.


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,该注释定义了一种额外的情况,即区域被视为未签名:“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,解析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 against zone enumeration and support Opt-Out. NSEC3 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是否可涵盖未签署的授权。”(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)

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.


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) Note that the roles KSK and ZSK are not mutually exclusive: a single key can be both KSK and ZSK at the same time. 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)注意,角色KSK和ZSK并非互斥:单个密钥可以同时为KSK和ZSK。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 validation.

安全入口点(SEP):DNSKEY RDATA中的一个标志,“可用于区分在建立信任链时用作区域安全入口点的密钥,即它们是(将是)由家长DS RRs指向或配置为信任锚点。因此,建议在用作KSK的密钥上设置SEP标志,而不是在用作ZSK的密钥上设置SEP标志,而在没有区分KSK和ZSK的情况下(即,对于单一类型签名方案)建议在所有钥匙上设置SEP标志。”(引用[RFC6781],第3.2.3节)注意,SEP标志只是一个提示,其存在或不存在不得用于取消给定DNSKEY RR在验证期间用作KSK或ZSK的资格。

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)


9. 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 two definitions differ a bit. This document makes no effort to reconcile the two definitions, 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 an attack but may also indicate a configuration error or some form of data corruption.

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。这种情况可能表示攻击,但也可能表示配置错误或某种形式的数据损坏。

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。

10. Security Considerations
10. 安全考虑

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


11. References
11. 工具书类
11.1. Normative References
11.1. 规范性引用文件

[RFC882] Mockapetris, P., "Domain names: Concepts and facilities", RFC 882, DOI 10.17487/RFC0882, November 1983, <>.

[RFC882]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<>.

[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<>.

[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<>.

[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<>.

[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<>.

[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<>.

11.2. Informative References
11.2. 资料性引用

[DBOUND] IETF, "Domain Boundaries (dbound) Working Group", 2015, <>.


[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<>.

[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<>.

[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<>.

[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<>.

[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<>.



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 have helped shape this document.

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这份文件。

Authors' Addresses


Paul Hoffman ICANN



Andrew Sullivan Dyn 150 Dow Street, Tower 2 Manchester, NH 03101 United States



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