draft-ietf-dnsop-dns-terminology-02.txt   draft-ietf-dnsop-dns-terminology-03.txt 
Network Working Group P. Hoffman Network Working Group P. Hoffman
Internet-Draft VPN Consortium Internet-Draft VPN Consortium
Intended status: Best Current Practice A. Sullivan Intended status: Best Current Practice A. Sullivan
Expires: November 27, 2015 Dyn Expires: December 24, 2015 Dyn
K. Fujiwara K. Fujiwara
JPRS JPRS
May 26, 2015 June 22, 2015
DNS Terminology DNS Terminology
draft-ietf-dnsop-dns-terminology-02 draft-ietf-dnsop-dns-terminology-03
Abstract Abstract
The DNS is defined in literally dozens of different RFCs. The The DNS is defined in literally dozens of different RFCs. The
terminology used in by implementers and developers of DNS protocols, terminology used in by implementers and developers of DNS protocols,
and by operators of DNS systems, has sometimes changed in the decades and by operators of DNS systems, has sometimes changed in the decades
since the DNS was first defined. This document gives current since the DNS was first defined. This document gives current
definitions for many of the terms used in the DNS in a single definitions for many of the terms used in the DNS in a single
document. document.
skipping to change at page 1, line 38 skipping to change at page 1, line 38
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 27, 2015. This Internet-Draft will expire on December 24, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 16 skipping to change at page 2, line 16
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. DNS Header and Response Codes . . . . . . . . . . . . . . . . 5 3. DNS Header and Response Codes . . . . . . . . . . . . . . . . 5
4. Resource Records . . . . . . . . . . . . . . . . . . . . . . 6 4. Resource Records . . . . . . . . . . . . . . . . . . . . . . 6
5. DNS Servers . . . . . . . . . . . . . . . . . . . . . . . . . 8 5. DNS Servers . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6. Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7. Registration Model . . . . . . . . . . . . . . . . . . . . . 14 7. Registration Model . . . . . . . . . . . . . . . . . . . . . 15
8. General DNSSEC . . . . . . . . . . . . . . . . . . . . . . . 15 8. General DNSSEC . . . . . . . . . . . . . . . . . . . . . . . 16
9. DNSSEC States . . . . . . . . . . . . . . . . . . . . . . . . 17 9. DNSSEC States . . . . . . . . . . . . . . . . . . . . . . . . 18
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
11. Security Considerations . . . . . . . . . . . . . . . . . . . 19 11. Security Considerations . . . . . . . . . . . . . . . . . . . 20
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
13.1. Normative References . . . . . . . . . . . . . . . . . . 20 13.1. Normative References . . . . . . . . . . . . . . . . . . 21
13.2. Informative References . . . . . . . . . . . . . . . . . 21 13.2. Informative References . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction 1. Introduction
The domain name system (DNS) is a simple query-response protocol The domain name system (DNS) is a simple query-response protocol
whose messages in both directions have the same format. The protocol whose messages in both directions have the same format. The protocol
and message format are defined in [RFC1034] and [RFC1035]. These and message format are defined in [RFC1034] and [RFC1035]. These
RFCs defined some terms, but later documents defined others. Some of RFCs defined some terms, but later documents defined others. Some of
the terms from RFCs 1034 and 1035 now have somewhat different the terms from RFCs 1034 and 1035 now have somewhat different
meanings than they did in 1987. meanings than they did in 1987.
skipping to change at page 2, line 49 skipping to change at page 2, line 49
loosely defined in earlier RFCs, and some are not defined in any loosely defined in earlier RFCs, and some are not defined in any
earlier RFC at all. earlier RFC at all.
The definitions here are believed to be the consensus definition of The definitions here are believed to be the consensus definition of
the DNS community, both protocol developers and operators. Some of the DNS community, both protocol developers and operators. Some of
the definitions differ from earlier RFCs, and those differences are the definitions differ from earlier RFCs, and those differences are
noted. The terms are organized loosely by topic. Some definitions noted. The terms are organized loosely by topic. Some definitions
are for new terms for things that are commonly talked about in the are for new terms for things that are commonly talked about in the
DNS community but that never had terms defined for them. DNS community but that never had terms defined for them.
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 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.
In this document, where the consensus definition is the same as the In this document, where the consensus definition is the same as the
one in an RFC, that RFC is quoted. Where the consensus definition one in an RFC, that RFC is quoted. Where the consensus definition
has changed somewhat, the RFC is mentioned but the new stand-alone has changed somewhat, the RFC is mentioned but the new stand-alone
definition is given. definition is given.
Other organizations sometimes define DNS-related terms their own way. Other organizations sometimes define DNS-related terms their own way.
For example, the W3C defines "domain" at For example, the W3C defines "domain" at
https://specs.webplatform.org/url/webspecs/develop/. https://specs.webplatform.org/url/webspecs/develop/.
Note that there is no single consistent definition of "the DNS". It Note that there is no single consistent definition of "the DNS". It
skipping to change at page 4, line 40 skipping to change at page 4, line 48
point of view of the DNS, about TLDs. Most of them are also point of view of the DNS, about TLDs. Most of them are also
delegation-centric zones, and there are significant policy issues delegation-centric zones, and there are significant policy issues
around their operation. TLDs are often divided into sub-groups around their operation. TLDs are often divided into sub-groups
such as "ccTLDs", "gTLDs", and others; the division is a matter of such as "ccTLDs", "gTLDs", and others; the division is a matter of
policy, and beyond the scope of this document. policy, and beyond the scope of this document.
IDN: The common abbreviation for "internationalized domain name". IDN: The common abbreviation for "internationalized domain name".
IDNs are the current standard mechanism for handling domain names IDNs are the current standard mechanism for handling domain names
with non-ASCII characters in applications. The current standard, with non-ASCII characters in applications. The current standard,
normally called "IDNA2008", is defined in [RFC5890], [RFC5891], normally called "IDNA2008", is defined in [RFC5890], [RFC5891],
[RFC5892], [RFC5893], and [RFC5894]. [RFC5892], [RFC5893], and [RFC5894]. These documents define many
IDN-specific terms such as "LDH label", "A-label", and "U-label".
Alias: The owner of a CNAME resource record, or a subdomain of the Alias: The owner of a CNAME resource record, or a subdomain of the
owner of a DNAME resource record [RFC6672]. See also "canonical owner of a DNAME resource record [RFC6672]. See also "canonical
name". name".
Canonical name: A CNAME resource record identifies its owner name as Canonical name: A CNAME resource record identifies its owner name as
an alias, and specifies the corresponding canonical name in the an alias, and specifies the corresponding canonical name in the
RDATA section of the RR. (Quoted from [RFC1034], section 3.6.2) RDATA section of the RR. (Quoted from [RFC1034], section 3.6.2)
This usage of the word "canonical" is related to the mathematical This usage of the word "canonical" is related to the mathematical
concept of "canonical form". concept of "canonical form".
skipping to change at page 5, line 34 skipping to change at page 5, line 44
public suffix is that designation can change over time as the public suffix is that designation can change over time as the
registration policy for the zone changes, such as the case of the registration policy for the zone changes, such as the case of the
.uk zone around the time this document is published. .uk zone around the time this document is published.
3. DNS Header and Response Codes 3. DNS Header and Response Codes
The header of a DNS message is first 12 octets. Many of the fields The header of a DNS message is first 12 octets. Many of the fields
and flags in the header diagram in section 4.1.1 of [RFC1035] are and flags in the header diagram in section 4.1.1 of [RFC1035] are
referred to by their names in that diagram. For example, the referred to by their names in that diagram. For example, the
response codes are called "RCODEs", the data for a record is called response codes are called "RCODEs", the data for a record is called
the "RDATA" (sometimes also called "RRdata"), and the authoritative the "RDATA", and the authoritative answer bit is often called "the AA
answer bit is often called "the AA flag" or "the AA bit". flag" or "the AA bit".
Some of response codes that are defined in [RFC1035] have gotten Some of response codes that are defined in [RFC1035] have gotten
their own shorthand names. Some common response code names that their own shorthand names. Some common response code names that
appear without reference to the numeric value are "FORMERR", appear without reference to the numeric value are "FORMERR",
"SERVFAIL", and "NXDOMAIN". All of the RCODEs are listed at "SERVFAIL", and "NXDOMAIN" (the latter of which is also referred to
as "Name Error"). All of the RCODEs are listed at
http://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml, http://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml,
although that site uses mixed-case capitalization, while most although that site uses mixed-case capitalization, while most
documents use all-caps. documents use all-caps.
NODATA: A pseudo RCODE which indicates that the name is valid for NODATA: A pseudo RCODE which indicates that the name is valid for
the given class, but are no records of the given type. A NODATA the given class, but are no records of the given type. A NODATA
response has to be inferred from the answer. (Quoted from response has to be inferred from the answer. (Quoted from
[RFC2308], section 1.) NODATA is indicated by an answer with the [RFC2308], section 1.) NODATA is indicated by an answer with the
RCODE set to NOERROR and no relevant answers in the answer RCODE set to NOERROR and no relevant answers in the answer
section. The authority section will contain an SOA record, or section. The authority section will contain an SOA record, or
skipping to change at page 6, line 29 skipping to change at page 6, line 39
may be a zone cut NS resource records and their glue records. NS may be a zone cut NS resource records and their glue records. NS
records on the parent side of a zone cut are an authoritative records on the parent side of a zone cut are an authoritative
delegation, but are normally not treated as authoritative data by delegation, but are normally not treated as authoritative data by
the client. In general, a referral is a way for a server to send the client. In general, a referral is a way for a server to send
an answer saying that the server does not know the answer, but an answer saying that the server does not know the answer, but
knows where the query should be directed in order to get an knows where the query should be directed in order to get an
answer. Historically, many authoritative servers answered with a answer. Historically, many authoritative servers answered with a
referral to the root zone when queried for a name for which they referral to the root zone when queried for a name for which they
were not authoritative, but this practice has declined. were not authoritative, but this practice has declined.
Zone transfer: The act of a client requesting a copy of a zone and
an authoritative server sending the needed information. 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.
4. Resource Records 4. Resource Records
RR: A short form for resource record. ([RFC1034], section 3.6.) RR: A short form for resource record. ([RFC1034], section 3.6.)
RRset: A set of resource records with the same label, class and RRset: A set of resource records with the same label, class and
type, but with different data. (Definition from [RFC2181]) Also type, but with different data. (Definition from [RFC2181]) Also
spelled RRSet in some documents. As a clarification, "same label" spelled RRSet in some documents. As a clarification, "same label"
in this definition means "same owner name". In addition, in this definition means "same owner name". In addition,
[RFC2181] states that "the TTLs of all RRs in an RRSet must be the [RFC2181] states that "the TTLs of all RRs in an RRSet must be the
same". same".
skipping to change at page 8, line 11 skipping to change at page 8, line 11
effectively becomes zero. Some servers do not honor the TTL on an effectively becomes zero. Some servers do not honor the TTL on an
RRset from the authoritative servers, such as when when the RRset from the authoritative servers, such as when when the
authoritative data has a very short TTL. authoritative data has a very short TTL.
There is also the concept of a "default TTL" for a zone, which can There is also the concept of a "default TTL" for a zone, which can
be a configuration parameter in the server software. This is be a configuration parameter in the server software. This is
often expressed by a default for the entire server, and a default 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 for a zone using the $TTL directive in a zone file. The $TTL
directive was added to the master file format by [RFC2308]. 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.
5. DNS Servers 5. DNS Servers
This section defines the terms used for the systems that act as DNS This section defines the terms used for the systems that act as DNS
clients, DNS servers, or both. Some terms about servers describe clients, DNS servers, or both. Some terms about servers describe
servers that do and do not use DNSSEC; see Section 8 for those servers that do and do not use DNSSEC; see Section 8 for those
definitions. definitions.
Resolver: A program that extracts information from name servers in Resolver: A program that extracts information from name servers in
response to client requests. (Quoted from [RFC1034], section 2.4) response to client requests. (Quoted from [RFC1034], section 2.4)
The resolver is located on the same machine as the program that The resolver is located on the same machine as the program that
skipping to change at page 9, line 24 skipping to change at page 9, line 30
term to mean a resolver that acts in recursive mode with a cache term to mean a resolver that acts in recursive mode with a cache
(and meets other requirements). (and meets other requirements).
Priming: The mechanism used by a resolver to determine where to send Priming: The mechanism used by a resolver to determine where to send
queries before there is anything in the resolver's cache. Priming queries before there is anything in the resolver's cache. Priming
is most often done from a configuration setting that contains a is most often done from a configuration setting that contains a
list of authoritative servers for the DNS root zone. list of authoritative servers for the DNS root zone.
Negative caching: The storage of knowledge that something does not Negative caching: The storage of knowledge that something does not
exist, cannot give an answer, or does not give an answer. (Quoted exist, cannot give an answer, or does not give an answer. (Quoted
from Section 1 of [RFC2308]) from [RFC2308], section 1)
Authoritative server: A server that knows the content of a DNS zone Authoritative server: A server that knows the content of a DNS zone
from local knowledge, and thus can answer queries about that zone from local knowledge, and thus can answer queries about that zone
without needing to query other servers. (Quoted from [RFC2182], without needing to query other servers. (Quoted from [RFC2182],
section 2.) It is a system that responds to DNS queries with section 2.) It is a system that responds to DNS queries with
information about zones for which it has been configured to answer 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 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 that has authority over one or more DNS zones. Note that it is
possible for an authoritative server to respond to a query without possible for an authoritative server to respond to a query without
the parent zone delegating authority to that server. the parent zone delegating authority to that server.
Authoritative servers also provide "referrals", usually to child Authoritative servers also provide "referrals", usually to child
zones delegated from them; these referrals have the AA bit set to 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 0 and come with referral data in the Authority and (if needed) the
Additional sections. Additional sections.
Authoritative-only server: A name server which only serves
authoritative data and ignore 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. 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 Secondary server: "An authoritative server which uses zone transfer
to retrieve the zone" (quoted from [RFC1996], section 2.1). to retrieve the zone" (quoted from [RFC1996], section 2.1).
[RFC2182] describes secondary servers in detail. Although early [RFC2182] describes secondary servers in detail. Although early
DNS RFCs such as [RFC1996] referred to this as a "slave", the DNS RFCs such as [RFC1996] referred to this as a "slave", the
current common usage has shifted to calling it a "secondary". current common usage has shifted to calling it a "secondary".
Slave server: See secondary server. Slave server: See secondary server.
Primary server: "Any authoritative server configured to be the Primary server: "Any authoritative server configured to be the
source of zone transfer for one or more [secondary] servers" source of zone transfer for one or more [secondary] servers"
skipping to change at page 10, line 16 skipping to change at page 10, line 38
"master", the current common usage has shifted to "primary". "master", the current common usage has shifted to "primary".
Master server: See primary server. Master server: See primary server.
Primary master: The primary master is named in the zone's SOA MNAME Primary master: The primary master is named in the zone's SOA MNAME
field and optionally by an NS resource record. (Quoted from field and optionally by an NS resource record. (Quoted from
[RFC1996], section 2.1) [RFC2136] defines "primary master" as [RFC1996], section 2.1) [RFC2136] defines "primary master" as
"Master server at the root of the AXFR/IXFR dependency graph. The "Master server at the root of the AXFR/IXFR dependency graph. The
primary master is named in the zone's SOA MNAME field and primary master is named in the zone's SOA MNAME field and
optionally by an NS RR. There is by definition only one primary optionally by an NS RR. There is by definition only one primary
master server per zone." 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.
Stealth server: This is the same as a slave server except that it is Stealth server: This is the same as a slave server except that it is
not listed in an NS resource record for the zone. (Quoted from not listed in an NS resource record for the zone. (Quoted from
[RFC1996], section 2.1) [RFC1996], section 2.1)
Hidden master: A stealth server that is a master for zone transfers. Hidden master: A stealth server that is a master for zone transfers.
In this arrangement, the master name server that processes the In this arrangement, the master name server that processes the
updates is unavailable to general hosts on the Internet; it is not updates is unavailable to general hosts on the Internet; it is not
listed in the NS RRset. (Quoted from [RFC6781], section 3.4.3.) listed in the NS RRset. (Quoted from [RFC6781], section 3.4.3.)
An earlier RFC, [RFC4641], said that the hidden master's name An earlier RFC, [RFC4641], said that the hidden master's name
skipping to change at page 11, line 18 skipping to change at page 11, line 41
objectionable content. In general, a stub resolver has no idea objectionable content. In general, a stub resolver has no idea
whether or not upstream resolvers implement such policy or, if whether or not upstream resolvers implement such policy or, if
they do, the exact policy about what changes will be made. In they do, the exact policy about what changes will be made. In
some cases, the user of the stub resolver has selected the policy- some cases, the user of the stub resolver has selected the policy-
implementing resolver with the explicit intention of using it to implementing resolver with the explicit intention of using it to
implement the policies. In other cases, policies are imposed implement the policies. In other cases, policies are imposed
without the user of the stub resolver being informed. without the user of the stub resolver being informed.
Open resolver: A full-service resolver that accepts and processes Open resolver: A full-service resolver that accepts and processes
queries from any (or nearly any) stub resolver. This is sometimes queries from any (or nearly any) stub resolver. This is sometimes
also called a "public resolver". 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 View: A configuration for a DNS server that allows it to provide
different answers depending on attributes of the query. different answers depending on attributes of the query.
Typically, views differ by the source IP address of a query, but 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 can also be based on the destination IP address, the type of query
(such as AXFR), whether or not it is recursive, and so on. Views (such as AXFR), whether or not it is recursive, and so on. Views
are often used to provide more names or different addresses to are often used to provide more names or different addresses to
queries from "inside" a protected network than to those "outside" queries from "inside" a protected network than to those "outside"
that network. Views are not a standardized part of the DNS, but that network. Views are not a standardized part of the DNS, but
they are widely implemented in server software. they are widely implemented in server software.
skipping to change at page 11, line 40 skipping to change at page 12, line 18
Passive DNS: A mechanism to collect large amounts of DNS data by Passive DNS: A mechanism to collect large amounts of DNS data by
storing DNS responses from servers. Some of these systems also storing DNS responses from servers. Some of these systems also
collect the DNS queries associated with the responses; this can collect the DNS queries associated with the responses; this can
raise privacy issues. Passive DNS databases can be used to answer raise privacy issues. Passive DNS databases can be used to answer
historical questions about DNS zones such as which records were historical questions about DNS zones such as which records were
available for them at what times in the past. Passive DNS available for them at what times in the past. Passive DNS
databases allow searching of the stored records on keys other than 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 just the name, such as "find all names which have A records of a
particular value". particular value".
Child-centric resolver: A DNS resolver that, instead of serving the Anycast: The practice of making a particular service address
NS RRset and glue records that it obtained from the parent of a available in multiple, discrete, autonomous locations, such that
zone, serves data from the authoritative servers for that zone. datagrams sent are routed to one of several available locations.
The term "child-centric" is meant as the opposite of "parent- (Quoted from [RFC4786], Section 2)
centric", which means a resolver that simply serves the NS RRset
and glue records for a zone that it obtained from the zone's
parent, without checking the authoritative servers for that zone.
6. Zones 6. Zones
This section defines terms that are used when discussing zones that This section defines terms that are used when discussing zones that
are being served or retrieved. are being served or retrieved.
Zone: A unit of organization of authoritative data. Zones can be Zone: A unit of organization of authoritative data. Zones can be
automatically distributed to the name servers which provide automatically distributed to the name servers which provide
redundant service for the data in a zone. (Quoted from [RFC1034], redundant service for the data in a zone. (Quoted from [RFC1034],
section 2.4). section 2.4).
skipping to change at page 12, line 23 skipping to change at page 12, line 46
Parent: The domain in which the Child is registered. (Quoted from Parent: The domain in which the Child is registered. (Quoted from
[RFC7344], section 1.1) Earlier, "parent name server" was defined [RFC7344], section 1.1) Earlier, "parent name server" was defined
in [RFC0882] as "the name server that has authority over the place in [RFC0882] as "the name server that has authority over the place
in the domain name space that will hold the new domain". in the domain name space that will hold the new domain".
Origin: Origin:
(a) The domain name that appears at the top of a zone (just below (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 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. zone is the same as the name of the domain at the zone's origin.
(Quoted from [RFC2181], section 6.) (Quoted from [RFC2181], section 6.) These days, this sense of
"origin" and "apex" (defined below) are often used
interchangeably.
(b) The domain name within which a given relative domain name (b) The domain name within which a given relative domain name
appears in zone files. Generally seen in the context of appears in zone files. Generally seen in the context of
"$ORIGIN", which is a control entry defined in [RFC1035], section "$ORIGIN", which is a control entry defined in [RFC1035], section
5.1, as part of the master file format. For example, if the 5.1, as part of the master file format. For example, if the
$ORIGIN is set to "example.org.", then a master file line for $ORIGIN is set to "example.org.", then a master file line for
"www" is in fact an entry for "www.example.org.". "www" is in fact an entry for "www.example.org.".
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".
Apex: The point in the tree at an owner of an SOA and corresponding Apex: The point in the tree at an owner of an SOA and corresponding
authoritative NS RRset. This is also called the "zone apex". authoritative NS RRset. This is also called the "zone apex".
[RFC4033] defines it as "the name at the child's side of a zone [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 cut". The "apex" can usefully be thought of as a data-theoretic
description of a tree structure, and "origin" is the name of the description of a tree structure, and "origin" is the name of the
same concept when it is implemented in zone files. The same concept when it is implemented in zone files. The
distinction is not always maintained in use, however, and one can distinction is not always maintained in use, however, and one can
find uses that conflict subtly with this definition. [RFC1034] find uses that conflict subtly with this definition. [RFC1034]
uses the term "top node of the zone" instead of "apex". uses the term "top node of the zone" instead of "apex". 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 Delegation: The process by which a separate zone is created in the
name space beneath the apex of a given domain. Delegation happens 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. 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 Delegation inherently happens at a zone cut. The term is also
commonly a noun: the new zone that is created by the act of commonly a noun: the new zone that is created by the act of
delegating. delegating.
Glue records: "[Resource records] which are not part of the Glue records: "[Resource records] which are not part of the
authoritative data [of the zone], and are address resource records authoritative data [of the zone], and are address resource records
skipping to change at page 13, line 31 skipping to change at page 14, line 11
records of delegated sub-zones (NS records), address records that records of delegated sub-zones (NS records), address records that
accompany those NS records (A, AAAA, etc), and any other stray accompany those NS records (A, AAAA, etc), and any other stray
data that might appear" ([RFC2181], section 5.4.1). Although glue data that might appear" ([RFC2181], section 5.4.1). Although glue
is sometimes used today with this wider definition in mind, the is sometimes used today with this wider definition in mind, the
context surrounding the [RFC2181] definition suggests it is context surrounding the [RFC2181] definition suggests it is
intended to apply to the use of glue within the document itself intended to apply to the use of glue within the document itself
and not necessarily beyond. and not necessarily beyond.
In-bailiwick: In-bailiwick:
(a) An adjective to describe a name server the name of which is (a) An adjective to describe a name server whose name is either
either subordinate to or (rarely) the same as the zone origin. subordinate to or (rarely) the same as the zone origin. In-
In-bailiwick name servers require glue in their parent zone. bailiwick name servers require glue in their parent zone.
(b) Data for which the server is either authoritative, or else (b) Data for which the server is either authoritative, or else
authoritative for an ancestor of the owner name. This sense of authoritative for an ancestor of the owner name. This sense of
the term normally is used when discussing the relevancy of glue the term normally is used when discussing the relevancy of glue
records in a response. For example, the server for the parent records in a response. For example, the server for the parent
zone example.com might reply with glue records for zone example.com might reply with glue records for
ns.child.example.com. Because the child.example.com zone is a ns.child.example.com. Because the child.example.com zone is a
descendant of the example.com zone, the glue records are in- descendant of the example.com zone, the glue records are in-
bailiwick. bailiwick.
Out-of-bailiwick: The antonym of in-bailiwick. Out-of-bailiwick: The antonym of in-bailiwick.
Authoritative data: All of the RRs attached to all of the nodes from 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 the top node of the zone down to leaf nodes or nodes above cuts
around the bottom edge of the zone. (Quoted from Section 4.2.1 of around the bottom edge of the zone. (Quoted from [RFC1034],
[RFC1034]) It is noted that this definition might inadvertently section 4.2.1) It is noted that this definition might
also include any NS records that appear in the zone, even those inadvertently also include any NS records that appear in the zone,
that might not truly be authoritative because there are identical even those that might not truly be authoritative because there are
NS RRs below the zone cut. This reveals the ambiguity in the identical NS RRs below the zone cut. This reveals the ambiguity
notion of authoritative data, because the parent-size NS records in the notion of authoritative data, because the parent-side NS
authoritatively indicate the delegation, even though they are not records authoritatively indicate the delegation, even though they
themselves authoritative data. are not themselves authoritative data.
Root zone: The zone whose origin is the zero-length label. Also Root zone: The zone whose apex is the zero-length label. Also
sometimes called "the DNS root". sometimes called "the DNS root".
Empty non-terminals: Domain names that own no resource records but Empty non-terminals: Domain names that own no resource records but
have subdomains that do. (Quoted from [RFC4592], section 2.2.2.) have subdomains that do. (Quoted from [RFC4592], section 2.2.2.)
A typical example is in SRV records: in the name A typical example is in SRV records: in the name
"_sip._tcp.example.com", it is likely that "_tcp.example.com" has "_sip._tcp.example.com", it is likely that "_tcp.example.com" has
no RRsets, but that "_sip._tcp.example.com" has (at least) an SRV no RRsets, but that "_sip._tcp.example.com" has (at least) an SRV
RRset. RRset.
Delegation-centric zone: A zone which consists mostly of delegations Delegation-centric zone: A zone which consists mostly of delegations
to child zones. This term is used in contrast to a zone which to child zones. This term is used in contrast to a zone which
might have some delegations to child zones, but also has many data might have some delegations to child zones, but also has many data
resource records for the zone itself and/or for child zones. The resource records for the zone itself and/or for child zones. The
term is used in [RFC4956] and [RFC5155], but is not defined there. term is used in [RFC4956] and [RFC5155], but is not defined there.
Wildcard: [RFC1034] defined "wildcard", but in a way that turned out Wildcard: [RFC1034] defined "wildcard", but in a way that turned out
to be confusing to implementers. For an extended discussion of to be confusing to implementers. Special treatment is given to
wildcards, including clearer definitions, see [RFC4592]. 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 Occluded name: The addition of a delegation point via dynamic update
will render all subordinate domain names to be in a limbo, still will render all subordinate domain names to be in a limbo, still
part of the zone but not available to the lookup process. The part of the zone but not available to the lookup process. The
addition of a DNAME resource record has the same impact. The addition of a DNAME resource record has the same impact. The
subordinate names are said to be "occluded". (Quoted from subordinate names are said to be "occluded". (Quoted from
[RFC5936], Section 3.5) [RFC5936], Section 3.5)
Fast flux DNS: This occurs when a domain is bound in DNS using A Fast flux DNS: This occurs when a domain is bound in DNS using A
records to multiple IP addresses, each of which has a very short records to multiple IP addresses, each of which has a very short
skipping to change at page 15, line 26 skipping to change at page 16, line 10
EPP: The Extensible Provisioning Protocol (EPP), which is commonly EPP: The Extensible Provisioning Protocol (EPP), which is commonly
used for communication of registration information between used for communication of registration information between
registries and registrars. EPP is defined in [RFC5730]. registries and registrars. EPP is defined in [RFC5730].
WHOIS: A protocol specified in [RFC3912], often used for querying WHOIS: A protocol specified in [RFC3912], often used for querying
registry databases. WHOIS data is frequently used to associate registry databases. WHOIS data is frequently used to associate
registration data (such as zone management contacts) with domain registration data (such as zone management contacts) with domain
names. names.
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.
8. General DNSSEC 8. General DNSSEC
Most DNSSEC terms are defined in [RFC4033], [RFC4034], and [RFC4035]. Most DNSSEC terms are defined in [RFC4033], [RFC4034], [RFC4035], and
The terms that have caused confusion in the DNS community are [RFC5155]. The terms that have caused confusion in the DNS community
highlighted here. are highlighted here.
DNSSEC-aware and DNSSEC-unaware: Section 2 of [RFC4033] defines many DNSSEC-aware and DNSSEC-unaware: Section 2 of [RFC4033] defines many
types of resolvers and validators. In specific, the terms "non- types of resolvers and validators, including "non-validating
validating security-aware stub resolver", "non-validating stub security-aware stub resolver", "non-validating stub resolver",
resolver", "security-aware name server", "security-aware recursive "security-aware name server", "security-aware recursive name
name server", "security-aware resolver", "security-aware stub server", "security-aware resolver", "security-aware stub
resolver", and "security-oblivious 'anything'" are all defined. resolver", and "security-oblivious 'anything'". (Note that the
(Note that the term "validating resolver", which is used in some term "validating resolver", which is used in some places in those
places in those documents, is nevertheless not defined in that documents, is nevertheless not defined in that section.)
section.)
Signed zone: A zone whose RRsets are signed and that contains Signed zone: A zone whose RRsets are signed and that contains
properly constructed DNSKEY, Resource Record Signature (RRSIG), properly constructed DNSKEY, Resource Record Signature (RRSIG),
Next Secure (NSEC), and (optionally) DS records. (Quoted from Next Secure (NSEC), and (optionally) DS records. (Quoted from
[RFC4033], section 2.) It has been noted in other contexts that [RFC4033], section 2.) It has been noted in other contexts that
the zone itself is not really signed, but all the relevant RRsets the zone itself is not really signed, but all the relevant RRsets
in the zone are signed. Nevertheless, if a zone that should be in the zone are signed. Nevertheless, if a zone that should be
signed contains any RRsets that are not signed (or opted out), signed contains any RRsets that are not signed (or opted out),
those RRsets will be treated as bogus, so the whole zone needs to 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 be handled in some way.
publication of [RFC6840], NSEC records are no longer required for
signed zones: a signed zone might include NSEC3 records instead. 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 Unsigned zone: Section 2 of [RFC4033] defines this as "a zone that
is not signed". Section 2 of [RFC4035] defines this as "A zone is not signed". Section 2 of [RFC4035] defines this as "A zone
that does not include these records [properly constructed DNSKEY, that does not include these records [properly constructed DNSKEY,
Resource Record Signature (RRSIG), Next Secure (NSEC), and Resource Record Signature (RRSIG), Next Secure (NSEC), and
(optionally) DS records] according to the rules in this section". (optionally) DS records] according to the rules in this section".
There is an important note at the end of Section 5.2 of [RFC4035] There is an important note at the end of Section 5.2 of [RFC4035]
adding an additional situation when a zone is considered unsigned: adding an additional situation when a zone is considered unsigned:
"If the resolver does not support any of the algorithms listed in "If the resolver does not support any of the algorithms listed in
an authenticated DS RRset, then the resolver will not be able to an authenticated DS RRset, then the resolver will not be able to
skipping to change at page 16, line 31 skipping to change at page 17, line 22
existence with the same mechanisms used to authenticate other DNS existence with the same mechanisms used to authenticate other DNS
replies." (Quoted from [RFC4033], section 3.2.) In short, an replies." (Quoted from [RFC4033], section 3.2.) In short, an
NSEC record provides authenticated denial of existence. NSEC record provides authenticated denial of existence.
The NSEC resource record lists two separate things: the next owner The NSEC resource record lists two separate things: the next owner
name (in the canonical ordering of the zone) that contains name (in the canonical ordering of the zone) that contains
authoritative data or a delegation point NS RRset, and the set of authoritative data or a delegation point NS RRset, and the set of
RR types present at the NSEC RR's owner name. (Quoted from RR types present at the NSEC RR's owner name. (Quoted from
Section 4 of 4034) Section 4 of 4034)
NSEC3: The NSEC3 resource record is quite different than the NSEC NSEC3: Like the NSEC record, the NSEC3 record also provides
resource record. Like the NSEC record, the NSEC3 record also authenticated denial of existence; however, NSEC3 records
provides authenticated denial of existence; however, NSEC3 records
mitigates against zone enumeration and support Opt-Out. NSEC3 mitigates against zone enumeration and support Opt-Out. NSEC3
resource records are defined in [RFC5155]. 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 Opt-out: The Opt-Out Flag indicates whether this NSEC3 RR may cover
unsigned delegations. (Quoted from [RFC5155], section 3.1.2.1.) unsigned delegations. (Quoted from [RFC5155], section 3.1.2.1.)
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)
Zone enumeration: The practice of discovering the full content of a Zone enumeration: The practice of discovering the full content of a
zone via successive queries. (Quoted from [RFC5155], section zone via successive queries. (Quoted from [RFC5155], section
1.3.) This is also sometimes call "zone walking". Zone 1.3.) This is also sometimes call "zone walking". Zone
enumeration is different from zone content guessing where the enumeration is different from zone content guessing where the
guesser uses a large dictionary of possible labels and sends guesser uses a large dictionary of possible labels and sends
successive queries for them, or matches the contents of NSEC3 successive queries for them, or matches the contents of NSEC3
records against such a dictionary. records against such a dictionary.
Key signing key (KSK): DNSSEC keys that only sign the apex DNSKEY Key signing key (KSK): DNSSEC keys that only sign the apex DNSKEY
RRset in a zone. (Quoted from [RFC6781], section 3.1.) RRset in a zone. (Quoted from [RFC6781], section 3.1)
Zone signing key (ZSK): DNSSEC keys that can be used to sign all the 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 RRsets in a zone that require signatures, other than the apex
DNSKEY RRset. (Quoted from [RFC6781], section 3.1) Note that the DNSKEY RRset. (Quoted from [RFC6781], section 3.1) Note that the
roles KSK and ZSK are not mutually exclusive: a single key can be roles KSK and ZSK are not mutually exclusive: a single key can be
both KSK and ZSK at the same time. both KSK and ZSK at the same time. Also note that a ZSK is
sometimes used to sign the apex DNSKEY RRset.
Combined signing key (CSK): In cases where the differentiation Combined signing key (CSK): In cases where the differentiation
between the KSK and ZSK is not made, i.e., where keys have the 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 role of both KSK and ZSK, we talk about a Single-Type Signing
Scheme. (Quoted from [RFC6781], Section 3.1) This is sometimes Scheme. (Quoted from [RFC6781], Section 3.1) This is sometimes
called a "combined signing key" or CSK. It is operational called a "combined signing key" or CSK. It is operational
practice, not protocol, that determines whether a particular key practice, not protocol, that determines whether a particular key
is a ZSK, a KSK, or a CSK. is a ZSK, a KSK, or a CSK.
Secure Entry Point (SEP): A flag in the DNSKEY RRdata that can be 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 used to distinguish between keys that are intended to be used as
the secure entry point into the zone when building chains of 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 trust, i.e., they are (to be) pointed to by parental DS RRs or
configured as a trust anchor. (Quoted from [RFC6781], section configured as a trust anchor. Therefore, it is suggested that the
3.2.3.) Note that the SEP flag is only a hint, and its presence SEP flag be set on keys that are used as KSKs and not on keys that
or absence may not be used to disqualify a given DNSKEY RR from are used as ZSKs, while in those cases where a distinction between
use as a KSK or ZSK during validation. 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.
DNSSEC Policy (DP): A statement that sets forth the security DNSSEC Policy (DP): A statement that sets forth the security
requirements and standards to be implemented for a DNSSEC-signed requirements and standards to be implemented for a DNSSEC-signed
zone. (Quoted from [RFC6841], section 2) zone. (Quoted from [RFC6841], section 2)
DNSSEC Practice Statement (DPS): A practices disclosure document DNSSEC Practice Statement (DPS): A practices disclosure document
that may support and be a supplemental document to the DNSSEC that may support and be a supplemental document to the DNSSEC
Policy (if such exists), and it states how the management of a Policy (if such exists), and it states how the management of a
given zone implements procedures and controls at a high level. given zone implements procedures and controls at a high level.
(Quoted from [RFC6841], section 2) (Quoted from [RFC6841], section 2)
skipping to change at page 19, line 36 skipping to change at page 20, line 36
corruption. corruption.
Indeterminate: An RRset for which the resolver is not able to Indeterminate: An RRset for which the resolver is not able to
determine whether the RRset should be signed, as the resolver is determine whether the RRset should be signed, as the resolver is
not able to obtain the necessary DNSSEC RRs. This can occur when not able to obtain the necessary DNSSEC RRs. This can occur when
the security-aware resolver is not able to contact security-aware the security-aware resolver is not able to contact security-aware
name servers for the relevant zones. name servers for the relevant zones.
10. IANA Considerations 10. IANA Considerations
This document has no effect on IANA registries. This document has no IANA actions.
11. Security Considerations 11. Security Considerations
These definitions do not change any security considerations for the These definitions do not change any security considerations for the
DNS. DNS.
12. Acknowledgements 12. Acknowledgements
The authors gratefully acknowledge all of the authors of DNS-related The authors gratefully acknowledge all of the authors of DNS-related
RFCs that proceed this one. Comments from Tony Finch, Stephane RFCs that proceed this one. Comments from Tony Finch, Stephane
skipping to change at page 22, line 14 skipping to change at page 23, line 14
[RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995,
August 1996. August 1996.
[RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912, [RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912,
September 2004. September 2004.
[RFC4641] Kolkman, O. and R. Gieben, "DNSSEC Operational Practices", [RFC4641] Kolkman, O. and R. Gieben, "DNSSEC Operational Practices",
RFC 4641, September 2006. RFC 4641, September 2006.
[RFC4697] Larson, M. and P. Barber, "Observed DNS Resolution
Misbehavior", BCP 123, RFC 4697, October 2006.
[RFC4786] Abley, J. and K. Lindqvist, "Operation of Anycast
Services", BCP 126, RFC 4786, December 2006.
[RFC4956] Arends, R., Kosters, M., and D. Blacka, "DNS Security [RFC4956] Arends, R., Kosters, M., and D. Blacka, "DNS Security
(DNSSEC) Opt-In", RFC 4956, July 2007. (DNSSEC) Opt-In", RFC 4956, July 2007.
[RFC5625] Bellis, R., "DNS Proxy Implementation Guidelines", BCP [RFC5625] Bellis, R., "DNS Proxy Implementation Guidelines", BCP
152, RFC 5625, August 2009. 152, RFC 5625, August 2009.
[RFC5890] Klensin, J., "Internationalized Domain Names for [RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework", Applications (IDNA): Definitions and Document Framework",
RFC 5890, August 2010. RFC 5890, August 2010.
skipping to change at page 22, line 42 skipping to change at page 23, line 48
Internationalized Domain Names for Applications (IDNA)", Internationalized Domain Names for Applications (IDNA)",
RFC 5893, August 2010. RFC 5893, August 2010.
[RFC5894] Klensin, J., "Internationalized Domain Names for [RFC5894] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Background, Explanation, and Applications (IDNA): Background, Explanation, and
Rationale", RFC 5894, August 2010. Rationale", RFC 5894, August 2010.
[RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265,
April 2011. April 2011.
[RFC7129] Gieben, R. and W. Mekking, "Authenticated Denial of
Existence in the DNS", RFC 7129, February 2014.
Authors' Addresses Authors' Addresses
Paul Hoffman Paul Hoffman
VPN Consortium VPN Consortium
127 Segre Place 127 Segre Place
Santa Cruz, CA 95060 Santa Cruz, CA 95060
USA USA
Email: paul.hoffman@vpnc.org Email: paul.hoffman@vpnc.org
Andrew Sullivan Andrew Sullivan
Dyn Dyn
150 Dow St, Tower 2 150 Dow St, Tower 2
Manchester, NH 1604 Manchester, NH 1604
USA USA
Email: asullivan@dyn.com Email: asullivan@dyn.com
Kazunori Fujiwara Kazunori Fujiwara
Japan Registry Services Co., Ltd. Japan Registry Services Co., Ltd.
 End of changes. 38 change blocks. 
88 lines changed or deleted 160 lines changed or added

This html diff was produced by rfcdiff 1.42. The latest version is available from http://tools.ietf.org/tools/rfcdiff/