draft-ietf-dnsext-wcard-clarify-06.txt   draft-ietf-dnsext-wcard-clarify-07.txt 
DNSEXT Working Group E. Lewis DNSEXT Working Group E. Lewis
INTERNET DRAFT NeuStar INTERNET DRAFT NeuStar
Expiration Date: November 11, 2005 May 11 2005 Expiration Date: November 16, 2005 May 16, 2005
The Role of Wildcards The Role of Wildcards
in the Domain Name System in the Domain Name System
draft-ietf-dnsext-wcard-clarify-06.txt draft-ietf-dnsext-wcard-clarify-07.txt
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
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Abstract Abstract
This is an update to the wildcard definition of RFC 1034. The This is an update to the wildcard definition of RFC 1034. The
interaction with wildcards and CNAME is changed, an error interaction with wildcards and CNAME is changed, an error
condition removed, and the words defining some concepts central to condition removed, and the words defining some concepts central
wildcards are changed. The overall goal is not to change wildcards, to wildcards are changed. The overall goal is not to change
but to refine the definition of RFC 1034. wildcards, but to refine the definition of RFC 1034.
1 Introduction 1 Introduction
In RFC 1034 [RFC1034], sections 4.3.2 and 4.3.3 describe the synthesis In RFC 1034 [RFC1034], sections 4.3.2 and 4.3.3 describe the
of answers from special resource records called wildcards. The synthesis of answers from special resource records called
definition in RFC 1034 is incomplete and has proven to be confusing. wildcards. The definition in RFC 1034 is incomplete and has
This document describes the wildcard synthesis by adding to the proven to be confusing. This document describes the wildcard
discussion and making limited modifications. Modifications are made synthesis by adding to the discussion and making limited
to close inconsistencies that have led to interoperability issues. modifications. Modifications are made to close inconsistencies
This description does not expand the service intended by the original that have led to interoperability issues. This description
definition. does not expand the service intended by the original definition.
Staying within the spirit and style of the original documents, this Staying within the spirit and style of the original documents,
document avoids specifying rules for DNS implementations regarding this document avoids specifying rules for DNS implementations
wildcards. The intention is to only describe what is needed for regarding wildcards. The intention is to only describe what is
interoperability, not restrict implementation choices. In addition, needed for interoperability, not restrict implementation choices.
consideration has been given to minimize any backwards compatibility In addition, consideration has been given to minimize any
with implementations that have complied with RFC 1034's definition. backwards compatibility with implementations that have complied
with RFC 1034's definition.
This document is focused on the concept of wildcards as defined in RFC This document is focused on the concept of wildcards as defined
1034. Nothing is implied regarding alternative approaches, nor are in RFC 1034. Nothing is implied regarding alternative approaches,
alternatives discussed. nor are alternatives discussed.
1.1 Motivation 1.1 Motivation
Many DNS implementations have diverged with respect to wildcards in Many DNS implementations have diverged with respect to wildcards
different ways from the original definition, or at from least what in different ways from the original definition, or at from least
had been intended. Although there is clearly a need to clarify the what had been intended. Although there is clearly a need to
original documents in light of this alone, the impetus for this clarify the original documents in light of this alone, the impetus
document lay in the engineering of the DNS security extensions for this document lay in the engineering of the DNS security
[RFC4033]. With an unclear definition of wildcards the design of extensions [RFC4033]. With an unclear definition of wildcards
authenticated denial became entangled. the design of authenticated denial became entangled.
This document is intended to limit changes, only those based on This document is intended to limit changes, only those based on
implementation experience, and to remain as close to the original implementation experience, and to remain as close to the original
document as possible. To reinforce this, relevant sections of RFC document as possible. To reinforce this, relevant sections of RFC
1034 are repeated verbatim to help compare the old and new text. 1034 are repeated verbatim to help compare the old and new text.
1.2 The Original Definition 1.2 The Original Definition
The context of the wildcard concept involves the algorithm by which The context of the wildcard concept involves the algorithm by
a name server prepares a response (in RFC 1034's section 4.3.2) and which a name server prepares a response (in RFC 1034's section
the way in which a resource record (set) is identified as being a 4.3.2) and the way in which a resource record (set) is identified
source of synthetic data (section 4.3.3). as being a source of synthetic data (section 4.3.3).
The beginning of the discussion ought to start with the definition The beginning of the discussion ought to start with the definition
of the term "wildcard" as it appears in RFC 1034, section 4.3.3. of the term "wildcard" as it appears in RFC 1034, section 4.3.3.
# In the previous algorithm, special treatment was given to RRs with # In the previous algorithm, special treatment was given to RRs with
# owner names starting with the label "*". Such RRs are called # owner names starting with the label "*". Such RRs are called
# wildcards. Wildcard RRs can be thought of as instructions for # wildcards. Wildcard RRs can be thought of as instructions for
# synthesizing RRs. When the appropriate conditions are met, the name # synthesizing RRs. When the appropriate conditions are met, the name
# server creates RRs with an owner name equal to the query name and # server creates RRs with an owner name equal to the query name and
# contents taken from the wildcard RRs. # contents taken from the wildcard RRs.
This passage appears after the algorithm in which the term wildcard This passage appears after the algorithm in which the term wildcard
is first used. In this definition, wildcard refers to resource is first used. In this definition, wildcard refers to resource
records. In other usage, wildcard has referred to domain names, and records. In other usage, wildcard has referred to domain names,
it has been used to describe the operational practice of relying on and it has been used to describe the operational practice of
wildcards to generate answers. It is clear from this that there is relying on wildcards to generate answers. It is clear from this
a need to define clear and unambiguous terminology in the process of that there is a need to define clear and unambiguous terminology
discussing wildcards. in the process of discussing wildcards.
The mention of the use of wildcards in the preparation of a response The mention of the use of wildcards in the preparation of a
is contained in step 3c of RFC 1034's section 4.3.2 entitled response is contained in step 3c of RFC 1034's section 4.3.2
"Algorithm." Note that "wildcard" does not appear in the algorithm, entitled "Algorithm." Note that "wildcard" does not appear in
instead references are made to the "*" label. The portion of the the algorithm, instead references are made to the "*" label.
algorithm relating to wildcards is deconstructed in detail in The portion of the algorithm relating to wildcards is
section 3 of this document, this is the beginning of the passage. deconstructed in detail in section 3 of this document, this is
the beginning of the passage.
# c. If at some label, a match is impossible (i.e., the # c. If at some label, a match is impossible (i.e., the
# corresponding label does not exist), look to see if [...] # corresponding label does not exist), look to see if [...]
# the "*" label exists. # the "*" label exists.
The scope of this document is the RFC 1034 definition of wildcards and The scope of this document is the RFC 1034 definition of
the implications of updates to those documents, such as DNSSEC. wildcards and the implications of updates to those documents,
Alternate schemes for synthesizing answers are not considered. such as DNSSEC. Alternate schemes for synthesizing answers are
(Note that there is no reference listed. No document is known to not considered. (Note that there is no reference listed. No
describe any alternate schemes, although there has been some document is known to describe any alternate schemes, although
mention of them in mailing lists.) there has been some mention of them in mailing lists.)
1.3 This Document 1.3 This Document
This document accomplishes these three items. This document accomplishes these three items.
o Defines new terms o Defines new terms
o Makes minor changes to avoid conflicting concepts o Makes minor changes to avoid conflicting concepts
o Describes the actions of certain resource records as wildcards o Describes the actions of certain resource records as wildcards
1.3.1 New Terms 1.3.1 New Terms
To help in discussing what resource records are wildcards, two terms To help in discussing what resource records are wildcards, two
will be defined - "asterisk label" and "wild card domain name". These terms will be defined - "asterisk label" and "wild card domain
are defined in section 2.1.1. name". These are defined in section 2.1.1.
To assist in clarifying the role of wildcards in the name server To assist in clarifying the role of wildcards in the name server
algorithm in RFC 1034, 4.3.2, "source of synthesis" and "closest algorithm in RFC 1034, 4.3.2, "source of synthesis" and "closest
encloser" are defined. These definitions are in section 3.3.2. encloser" are defined. These definitions are in section 3.3.2.
"Label match" is defined in section 3.2. "Label match" is defined in section 3.2.
The introduction of new terms ought not have an impact on any existing The introduction of new terms ought not have an impact on any
implementations. The new terms are used only to make discussions of existing implementations. The new terms are used only to make
wildcards clearer. discussions of wildcards clearer.
1.3.2 Changed Text 1.3.2 Changed Text
The definition of "existence" is changed, superficially. This The definition of "existence" is changed, superficially. This
change will not be apparent to implementations; it is needed to change will not be apparent to implementations; it is needed to
make descriptions more precise. The change appears in section 2.2.3. make descriptions more precise. The change appears in section
2.2.3.
RFC 1034, section 4.3.3., seems to prohibit having two asterisk RFC 1034, section 4.3.3., seems to prohibit having two asterisk
labels in a wildcard owner name. With this document the restriction labels in a wildcard owner name. With this document the
is removed entirely. This change and its implications are in restriction is removed entirely. This change and its implications
section 2.1.3. are in section 2.1.3.
The actions when a source of synthesis owns a CNAME RR are changed to The actions when a source of synthesis owns a CNAME RR are
mirror the actions if an exact match name owns a CNAME RR. This changed to mirror the actions if an exact match name owns a
is an addition to the words in RFC 1034, section 4.3.2, step 3, CNAME RR. This is an addition to the words in RFC 1034,
part c. The discussion of this is in section 3.3.3. section 4.3.2, step 3, part c. The discussion of this is in
section 3.3.3.
Only the latter change represents an impact to implementations. The Only the latter change represents an impact to implementations.
definition of existence is not a protocol impact. The change to the The definition of existence is not a protocol impact. The change
restriction on names is unlikely to have an impact, as there was no to the restriction on names is unlikely to have an impact, as
discussion of how to enforce the restriction. there was no discussion of how to enforce the restriction.
1.3.3 Considerations with Special Types 1.3.3 Considerations with Special Types
This document describes semantics of wildcard CNAME RRSets [RFC2181], This document describes semantics of wildcard CNAME RRSets
wildcard NS RRSets, wildcard SOA RRSets, wildcard DNAME RRSets [RFC2181], wildcard NS RRSets, wildcard SOA RRSets, wildcard
[RFC2672], wildcard DS RRSets [RFC TBD], and empty non-terminal DNAME RRSets [RFC2672], wildcard DS RRSets [RFC TBD], and empty
wildcards. Understanding these types in the context of wildcards non-terminal wildcards. Understanding these types in the context
has been clouded because these types incur special processing if they of wildcards has been clouded because these types incur special
are the result of an exact match. This discussion is in section 4. processing if they are the result of an exact match. This
discussion is in section 4.
These discussions do not have an implementation impact, they cover These discussions do not have an implementation impact, they cover
existing knowledge of the types, but to a greater level of detail. existing knowledge of the types, but to a greater level of detail.
1.4 Standards Terminology 1.4 Standards Terminology
This document does not use terms as defined in "Key words for use in This document does not use terms as defined in "Key words for use
RFCs to Indicate Requirement Levels." [RFC2119] in RFCs to Indicate Requirement Levels." [RFC2119]
Quotations of RFC 1034 are denoted by a '#' in the leftmost column. Quotations of RFC 1034 are denoted by a '#' in the leftmost
column.
2 Wildcard Syntax 2 Wildcard Syntax
The syntax of a wildcard is the same as any other DNS resource record, The syntax of a wildcard is the same as any other DNS resource
across all classes and types. The only significant feature is the record, across all classes and types. The only significant
owner name. feature is the owner name.
Because wildcards are encoded as resource records with special names, Because wildcards are encoded as resource records with special
they are included in zone transfers and incremental zone transfers. names, they are included in zone transfers and incremental zone
[RFC1995]. This feature has been underappreciated until discussions transfers[RFC1995]. This feature has been underappreciated until
on alternative approaches to wildcards appeared on mailing lists. discussions on alternative approaches to wildcards appeared on
mailing lists.
2.1 Identifying a Wildcard 2.1 Identifying a Wildcard
To provide a more accurate description of "wildcards", the definition To provide a more accurate description of "wildcards", the
has to start with a discussion of the domain names that appear as definition has to start with a discussion of the domain names
owners. Two new terms are needed, "Asterisk Label" and "Wild Card that appear as owners. Two new terms are needed, "Asterisk
Domain Name." Label" and "Wild Card Domain Name."
2.1.1 Wild Card Domain Name and Asterisk Label 2.1.1 Wild Card Domain Name and Asterisk Label
A "wild card domain name" is defined by having its initial A "wild card domain name" is defined by having its initial
(i.e., left-most or least significant) label be, in binary format: (i.e., left-most or least significant) label be, in binary format:
0000 0001 0010 1010 (binary) = 0x01 0x2a (hexadecimal) 0000 0001 0010 1010 (binary) = 0x01 0x2a (hexadecimal)
The first octet is the normal label type and length for a 1 octet The first octet is the normal label type and length for a 1 octet
long label, the second octet is the ASCII representation [RFC20] for long label, the second octet is the ASCII representation [RFC20]
the '*' character. for the '*' character.
A descriptive name of a label equaling that value is an "asterisk A descriptive name of a label equaling that value is an "asterisk
label." label."
RFC 1034's definition of wildcard would be "a resource record owned RFC 1034's definition of wildcard would be "a resource record
by a wild card domain name." owned by a wild card domain name."
2.1.2 Asterisks and Other Characters 2.1.2 Asterisks and Other Characters
No label values other than that in section 2.1.1 are asterisk labels, No label values other than that in section 2.1.1 are asterisk
hence names beginning with other labels are never wild card domain labels, hence names beginning with other labels are never wild
names. Labels such as 'the*' and '**' are not asterisk labels, card domain names. Labels such as 'the*' and '**' are not
they do not start wild card domain names. asterisk labels, they do not start wild card domain names.
2.1.3 Non-terminal Wild Card Domain Names 2.1.3 Non-terminal Wild Card Domain Names
In section 4.3.3, the following is stated: In section 4.3.3, the following is stated:
# .......................... The owner name of the wildcard RRs is of # .......................... The owner name of the wildcard RRs is of
# the form "*.<anydomain>", where <anydomain> is any domain name. # the form "*.<anydomain>", where <anydomain> is any domain name.
# <anydomain> should not contain other * labels...................... # <anydomain> should not contain other * labels......................
This restriction is lifted because the original documentation of it This restriction is lifted because the original documentation of it
is incomplete and the restriction does not serve any purpose given is incomplete and the restriction does not serve any purpose given
years of operational experience. years of operational experience.
Indirectly, the above passage raises questions about wild card domain Indirectly, the above passage raises questions about wild card
names having subdomains and possibly being an empty non-terminal. By domain names having subdomains and possibly being an empty
thinking of domain names such as "*.example.*.example." and non-terminal. By thinking of domain names such as
"*.*.example." and focusing on the right-most asterisk label in each, "*.example.*.example." and "*.*.example." and focusing on the
the issues become apparent. right-most asterisk label in each, the issues become apparent.
Although those example names have been restricted per RFC 1034, a name Although those example names have been restricted per RFC 1034,
such as "example.*.example." illustrates the same problems. The a name such as "example.*.example." illustrates the same problems.
sticky issue of subdomains and empty non-terminals is not removed by The sticky issue of subdomains and empty non-terminals is not
the restriction. With that conclusion, the restriction appears to removed by the restriction. With that conclusion, the restriction
be meaningless, worse yet, it implies that an implementation would appears to be meaningless, worse yet, it implies that an
have to perform checks that do little more than waste CPU cycles. implementation would have to perform checks that do little more
than waste CPU cycles.
A wild card domain name can have subdomains. There is no need to A wild card domain name can have subdomains. There is no need
inspect the subdomains to see if there is another asterisk label in to inspect the subdomains to see if there is another asterisk
any subdomain. label in any subdomain.
A wild card domain name can be an empty non-terminal. (See the A wild card domain name can be an empty non-terminal. (See the
upcoming sections on empty non-terminals.) In this case, any upcoming sections on empty non-terminals.) In this case, any
lookup encountering it will terminate as would any empty lookup encountering it will terminate as would any empty
non-terminal match. non-terminal match.
2.2 Existence Rules 2.2 Existence Rules
The notion that a domain name 'exists' is mentioned in the definition The notion that a domain name 'exists' is mentioned in the
of wildcards. In section 4.3.3 of RFC 1034: definition of wildcards. In section 4.3.3 of RFC 1034:
# Wildcard RRs do not apply: # Wildcard RRs do not apply:
# #
... ...
# - When the query name or a name between the wildcard domain and # - When the query name or a name between the wildcard domain and
# the query name is know[n] to exist. For example, if a wildcard # the query name is know[n] to exist. For example, if a wildcard
RFC 1034 also refers to non-existence in the process of generating RFC 1034 also refers to non-existence in the process of generating
a response that results in a return code of "name error." NXDOMAIN a response that results in a return code of "name error."
is introduced in RFC 2308, section 2.1 says "In this case the domain NXDOMAIN is introduced in RFC 2308, section 2.1 says "In this
... does not exist." The overloading of the term "existence" is case the domain ... does not exist." The overloading of the term
confusing. "existence" is confusing.
For the purposes of this document, a domain name is said to exist if For the purposes of this document, a domain name is said to
it plays a role in the execution of the algorithms in RFC 1034. This exist if it plays a role in the execution of the algorithms in
document avoids discussion determining when an authoritative name RFC 1034. This document avoids discussion determining when an
error has occurred. authoritative name error has occurred.
2.2.1 An Example 2.2.1 An Example
To illustrate what is meant by existence consider this complete zone: To illustrate what is meant by existence consider this complete
zone:
$ORIGIN example. $ORIGIN example.
example. 3600 IN SOA <SOA RDATA> example. 3600 IN SOA <SOA RDATA>
example. 3600 NS ns.example.com. example. 3600 NS ns.example.com.
example. 3600 NS ns.example.net. example. 3600 NS ns.example.net.
*.example. 3600 TXT "this is a wild card" *.example. 3600 TXT "this is a wild card"
*.example. 3600 MX 10 host1.example. *.example. 3600 MX 10 host1.example.
sub.*.example. 3600 TXT "this is not a wild card" sub.*.example. 3600 TXT "this is not a wild card"
host1.example. 3600 A 192.0.4.1 host1.example. 3600 A 192.0.4.1
_ssh._tcp.host1.example. 3600 SRV <SRV RDATA> _ssh._tcp.host1.example. 3600 SRV <SRV RDATA>
skipping to change at line 319 skipping to change at line 329
/ / \ \ / / \ \
/ / \ \ / / \ \
* host1 host2 subdel * host1 host2 subdel
| | | | | |
| | | | | |
sub _tcp _tcp sub _tcp _tcp
| | | |
| | | |
_ssh _ssh _ssh _ssh
The following queries would be synthesized from one of the wildcards: The following queries would be synthesized from one of the
wildcards:
QNAME=host3.example. QTYPE=MX, QCLASS=IN QNAME=host3.example. QTYPE=MX, QCLASS=IN
the answer will be a "host3.example. IN MX ..." the answer will be a "host3.example. IN MX ..."
QNAME=host3.example. QTYPE=A, QCLASS=IN QNAME=host3.example. QTYPE=A, QCLASS=IN
the answer will reflect "no error, but no data" the answer will reflect "no error, but no data"
because there is no A RR set at '*.example.' because there is no A RR set at '*.example.'
QNAME=foo.bar.example. QTYPE=TXT, QCLASS=IN QNAME=foo.bar.example. QTYPE=TXT, QCLASS=IN
the answer will be "foo.bar.example. IN TXT ..." the answer will be "foo.bar.example. IN TXT ..."
because bar.example. does not exist, but the wildcard does. because bar.example. does not exist, but the wildcard
does.
The following queries would not be synthesized from any of the The following queries would not be synthesized from any of the
wildcards: wildcards:
QNAME=host1.example., QTYPE=MX, QCLASS=IN QNAME=host1.example., QTYPE=MX, QCLASS=IN
because host1.example. exists because host1.example. exists
QNAME=ghost.*.example., QTYPE=MX, QCLASS=IN QNAME=ghost.*.example., QTYPE=MX, QCLASS=IN
because *.example. exists because *.example. exists
skipping to change at line 352 skipping to change at line 364
because sub.*.example. exists because sub.*.example. exists
QNAME=_telnet._tcp.host1.example., QTYPE=SRV, QCLASS=IN QNAME=_telnet._tcp.host1.example., QTYPE=SRV, QCLASS=IN
because _tcp.host1.example. exists (without data) because _tcp.host1.example. exists (without data)
QNAME=host.subdel.example., QTYPE=A, QCLASS=IN QNAME=host.subdel.example., QTYPE=A, QCLASS=IN
because subdel.example. exists (and is a zone cut) because subdel.example. exists (and is a zone cut)
2.2.2 Empty Non-terminals 2.2.2 Empty Non-terminals
Empty non-terminals [RFC2136, Section 7.16] are domain names that own Empty non-terminals [RFC2136, Section 7.16] are domain names
no resource records but have subdomains that do. In section 2.2.1, that own no resource records but have subdomains that do. In
"_tcp.host1.example." is an example of a empty non-terminal name. section 2.2.1, "_tcp.host1.example." is an example of a empty
Empty non-terminals are introduced by this text in section 3.1 of RFC non-terminal name. Empty non-terminals are introduced by this
1034: text in section 3.1 of RFC 1034:
# The domain name space is a tree structure. Each node and leaf on the # The domain name space is a tree structure. Each node and leaf on
# tree corresponds to a resource set (which may be empty). The domain # the tree corresponds to a resource set (which may be empty). The
# system makes no distinctions between the uses of the interior nodes # domain system makes no distinctions between the uses of the
# and leaves, and this memo uses the term "node" to refer to both. # interior nodes and leaves, and this memo uses the term "node" to
# refer to both.
The parenthesized "which may be empty" specifies that empty non- The parenthesized "which may be empty" specifies that empty non-
terminals are explicitly recognized, and that empty non-terminals terminals are explicitly recognized, and that empty non-terminals
"exist." "exist."
Pedantically reading the above paragraph can lead to an Pedantically reading the above paragraph can lead to an
interpretation that all possible domains exist - up to the suggested interpretation that all possible domains exist - up to the
limit of 255 octets for a domain name [RFC1035]. For example, suggested limit of 255 octets for a domain name [RFC1035].
www.example. may have an A RR, and as far as is practically For example, www.example. may have an A RR, and as far as is
concerned, is a leaf of the domain tree. But the definition can be practically concerned, is a leaf of the domain tree. But the
taken to mean that sub.www.example. also exists, albeit with no data. definition can be taken to mean that sub.www.example. also
By extension, all possible domains exist, from the root on down. As exists, albeit with no data. By extension, all possible domains
RFC 1034 also defines "an authoritative name error indicating that exist, from the root on down. As RFC 1034 also defines "an
the name does not exist" in section 4.3.1, this is not the intent of authoritative name error indicating that the name does not exist"
the original document. in section 4.3.1, this is not the intent of the original document.
2.2.3 Yet Another Definition of Existence 2.2.3 Yet Another Definition of Existence
RFC1034's wording is fixed by the following paragraph: RFC1034's wording is fixed by the following paragraph:
The domain name space is a tree structure. Nodes in the tree either The domain name space is a tree structure. Nodes in the tree
own at least one RRSet and/or have descendants that collectively own either own at least one RRSet and/or have descendants that
at least on RRSet. A node may have no RRSets if it has descendents collectively own at least on RRSet. A node may have no RRSets
that do, this node is a empty non-terminal. A node may have its own if it has descendents that do, this node is a empty non-terminal.
RRSets and have descendants with RRSets too. A node may have its own RRSets and have descendants with RRSets
too.
A node with no descendants is a leaf node. Empty leaf nodes do not A node with no descendants is a leaf node. Empty leaf nodes do
exist. not exist.
Note that at a zone boundary, the domain name owns data, including Note that at a zone boundary, the domain name owns data,
the NS RR set. At the delegating server, the NS RR set is not including the NS RR set. At the delegating server, the NS RR
authoritative, but that is of no consequence here. The domain name set is not authoritative, but that is of no consequence here.
owns data, therefore, it exists. The domain name owns data, therefore, it exists.
2.3 When does a Wild Card Domain Name is not Special 2.3 When does a Wild Card Domain Name is not Special
When a wild card domain name appears in a message's query section, When a wild card domain name appears in a message's query section,
no special processing occurs. An asterisk label in a query name no special processing occurs. An asterisk label in a query name
only (label) matches an asterisk label in the existing zone tree only (label) matches an asterisk label in the existing zone tree
when the 4.3.2 algorithm is being followed. when the 4.3.2 algorithm is being followed.
When a wild card domain name appears in the resource data of a When a wild card domain name appears in the resource data of a
record, no special processing occurs. An asterisk label in that record, no special processing occurs. An asterisk label in that
context literally means just an asterisk. context literally means just an asterisk.
3. Impact of a Wild Card Domain Name On a Response 3. Impact of a Wild Card Domain Name On a Response
The description of how wildcards impact response generation is in The description of how wildcards impact response generation is in
RFC 1034, section 4.3.2. That passage contains the algorithm RFC 1034, section 4.3.2. That passage contains the algorithm
followed by a server in constructing a response. Within that followed by a server in constructing a response. Within that
algorithm, step 3, part 'c' defines the behavior of the wild card. algorithm, step 3, part 'c' defines the behavior of the wild card.
The algorithm in RFC 1034, section 4.3.2. is not intended to be pseudo The algorithm in RFC 1034, section 4.3.2. is not intended to be
code, i.e., its steps are not intended to be followed in strict pseudo code, i.e., its steps are not intended to be followed in
order. The "algorithm" is a suggestion. As such, in step 3, parts strict order. The "algorithm" is a suggestion. As such, in
a, b, and c, do not have to be implemented in that order. step 3, parts a, b, and c, do not have to be implemented in
that order.
3.1 Step 2 3.1 Step 2
Step 2 of the RFC 1034's section 4.3.2 reads: Step 2 of the RFC 1034's section 4.3.2 reads:
# 2. Search the available zones for the zone which is the nearest # 2. Search the available zones for the zone which is the nearest
# ancestor to QNAME. If such a zone is found, go to step 3, # ancestor to QNAME. If such a zone is found, go to step 3,
# otherwise step 4. # otherwise step 4.
In this step, the most appropriate zone for the response is chosen. In this step, the most appropriate zone for the response is
The significance of this step is that it means all of step 3 is being chosen. The significance of this step is that it means all of
performed within one zone. This has significance when considering step 3 is being performed within one zone. This has significance
whether or not an SOA RR can be ever be used for synthesis. when considering whether or not an SOA RR can be ever be used for
synthesis.
3.2 Step 3 3.2 Step 3
Step 3 is dominated by three parts, labelled 'a', 'b', and 'c'. But Step 3 is dominated by three parts, labelled 'a', 'b', and 'c'.
the beginning of the step is important and needs explanation. But the beginning of the step is important and needs explanation.
# 3. Start matching down, label by label, in the zone. The # 3. Start matching down, label by label, in the zone. The
# matching process can terminate several ways: # matching process can terminate several ways:
The word 'matching' refers to label matching. The concept The word 'matching' refers to label matching. The concept
is based in the view of the zone as the tree of existing names. The is based in the view of the zone as the tree of existing names.
query name is considered to be an ordered sequence of labels - as The query name is considered to be an ordered sequence of
if the name were a path from the root to the owner of the desired labels - as if the name were a path from the root to the owner
data. (Which it is - 3rd paragraph of RFC 1034, section 3.1.) of the desired data. (Which it is - 3rd paragraph of RFC 1034,
section 3.1.)
The process of label matching a query name ends in exactly one of The process of label matching a query name ends in exactly one of
three choices, the parts 'a', 'b', and 'c'. Either the name is three choices, the parts 'a', 'b', and 'c'. Either the name is
found, the name is below a cut point, or the name is not found. found, the name is below a cut point, or the name is not found.
Once one of the parts is chosen, the other parts are not considered. Once one of the parts is chosen, the other parts are not
(E.g., do not execute part 'c' and then change the execution path to considered. (E.g., do not execute part 'c' and then change
finish in part 'b'.) The process of label matching is also done the execution path to finish in part 'b'.) The process of label
independent of the query type (QTYPE). matching is also done independent of the query type (QTYPE).
Parts 'a' and 'b' are not an issue for this clarification as they Parts 'a' and 'b' are not an issue for this clarification as they
do not relate to record synthesis. Part 'a' is an exact match that do not relate to record synthesis. Part 'a' is an exact match
results in an answer, part 'b' is a referral. It is possible, from that results in an answer, part 'b' is a referral. It is
the description given, that a query might fit into both part a and possible, from the description given, that a query might fit
part b, this is not within the scope of this document. into both part a and part b, this is not within the scope of
this document.
3.3 Part 'c' 3.3 Part 'c'
The context of part 'c' is that the process of label matching the The context of part 'c' is that the process of label matching the
labels of the query name has resulted in a situation in which there labels of the query name has resulted in a situation in which
is no corresponding label in the tree. It is as if the lookup has there is no corresponding label in the tree. It is as if the
"fallen off the tree." lookup has "fallen off the tree."
# c. If at some label, a match is impossible (i.e., the # c. If at some label, a match is impossible (i.e., the
# corresponding label does not exist), look to see if [...] # corresponding label does not exist), look to see if [...]
# the "*" label exists. # the "*" label exists.
To help describe the process of looking 'to see if [...] the "*" To help describe the process of looking 'to see if [...] the "*"
label exists' a term has been coined to describe the last domain label exists' a term has been coined to describe the last domain
(node) matched. The term is "closest encloser." (node) matched. The term is "closest encloser."
3.3.1 Closest Encloser and the Source of Synthesis 3.3.1 Closest Encloser and the Source of Synthesis
The closest encloser is the node in the zone's tree of existing The closest encloser is the node in the zone's tree of existing
domain names that has the most labels matching the query name domain names that has the most labels matching the query name
(consecutively, counting from the root label downward). Each match (consecutively, counting from the root label downward). Each match
is a "label match" and the order of the labels is the same. is a "label match" and the order of the labels is the same.
The closest encloser is, by definition, an existing name in the zone. The closest encloser is, by definition, an existing name in the
The closest encloser might be an empty non-terminal or even be a wild zone. The closest encloser might be an empty non-terminal or even
card domain name itself. In no circumstances is the closest encloser be a wild card domain name itself. In no circumstances is the
to be used to synthesize records for the current query. closest encloser to be used to synthesize records for the current
query.
The source of synthesis is defined in the context of a query process The source of synthesis is defined in the context of a query
as that wild card domain name immediately descending from the process as that wild card domain name immediately descending
closest encloser, provided that this wild card domain name exists. from the closest encloser, provided that this wild card domain
"Immediately descending" means that the source of synthesis has a name name exists. "Immediately descending" means that the source
of the form <asterisk label>.<closest encloser>. A source of of synthesis has a name of the form:
synthesis does not guarantee having a RRSet to use for synthesis. <asterisk label>.<closest encloser>.
The source of synthesis could be an empty non-terminal. A source of synthesis does not guarantee having a RRSet to use
for synthesis. The source of synthesis could be an empty
non-terminal.
If the source of synthesis does not exist (not on the domain tree), If the source of synthesis does not exist (not on the domain
there will be no wildcard synthesis. There is no search for an tree), there will be no wildcard synthesis. There is no search
alternate. for an alternate.
The important concept is that for any given lookup process, there The important concept is that for any given lookup process, there
is at most one place at which wildcard synthetic records can be is at most one place at which wildcard synthetic records can be
obtained. If the source of synthesis does not exist, the lookup obtained. If the source of synthesis does not exist, the lookup
terminates, the lookup does not look for other wildcard records. terminates, the lookup does not look for other wildcard records.
3.3.2 Closest Encloser and Source of Synthesis Examples 3.3.2 Closest Encloser and Source of Synthesis Examples
To illustrate, using the example zone in section 2.2.1 of this To illustrate, using the example zone in section 2.2.1 of this
document, the following chart shows QNAMEs and the closest enclosers. document, the following chart shows QNAMEs and the closest
enclosers.
QNAME Closest Encloser Source of Synthesis QNAME Closest Encloser Source of Synthesis
host3.example. example. *.example. host3.example. example. *.example.
_telnet._tcp.host1.example. _tcp.host1.example. no source _telnet._tcp.host1.example. _tcp.host1.example. no source
_telnet._tcp.host2.example. host2.example. no source _telnet._tcp.host2.example. host2.example. no source
_telnet._tcp.host3.example. example. *.example. _telnet._tcp.host3.example. example. *.example.
_chat._udp.host3.example. example. *.example. _chat._udp.host3.example. example. *.example.
foobar.*.example. *.example. no source foobar.*.example. *.example. no source
3.3.3 Type Matching 3.3.3 Type Matching
skipping to change at line 536 skipping to change at line 558
# response and exit. Otherwise just exit. # response and exit. Otherwise just exit.
# #
# If the "*" label does exist, match RRs at that node # If the "*" label does exist, match RRs at that node
# against QTYPE. If any match, copy them into the answer # against QTYPE. If any match, copy them into the answer
# section, but set the owner of the RR to be QNAME, and # section, but set the owner of the RR to be QNAME, and
# not the node with the "*" label. Go to step 6. # not the node with the "*" label. Go to step 6.
The final paragraph covers the role of the QTYPE in the lookup The final paragraph covers the role of the QTYPE in the lookup
process. process.
Based on implementation feedback and similarities between step 'a' and Based on implementation feedback and similarities between step
step 'c' a change to this passage has been made. 'a' and step 'c' a change to this passage has been made.
The change is to add the following text to step 'c': The change is to add the following text to step 'c':
If the data at the source of synthesis is a CNAME, and If the data at the source of synthesis is a CNAME, and
QTYPE doesn't match CNAME, copy the CNAME RR into the QTYPE doesn't match CNAME, copy the CNAME RR into the
answer section of the response changing the owner name answer section of the response changing the owner name
to the QNAME, change QNAME to the canonical name in the to the QNAME, change QNAME to the canonical name in the
CNAME RR, and go back to step 1. CNAME RR, and go back to step 1.
This is essentially the same text in step a covering the processing of This is essentially the same text in step a covering the
CNAME RRSets. processing of CNAME RRSets.
4. Considerations with Special Types 4. Considerations with Special Types
Sections 2 and 3 of this document discuss wildcard synthesis with Sections 2 and 3 of this document discuss wildcard synthesis
respect to names in the domain tree and ignore the impact of types. with respect to names in the domain tree and ignore the impact
In this section, the implication of wildcards of specific types are of types. In this section, the implication of wildcards of
discussed. The types covered are those that have proven to be the specific types are discussed. The types covered are those
most difficult to understand. The types are SOA, NS, CNAME, DNAME, that have proven to be the most difficult to understand. The
SRV, DS, NSEC, RRSIG and "none," i.e., empty non-terminal wild card types are SOA, NS, CNAME, DNAME, SRV, DS, NSEC, RRSIG and
domain names. "none," i.e., empty non-terminal wild card domain names.
4.1 SOA RRSet at a Wild Card Domain Name 4.1 SOA RRSet at a Wild Card Domain Name
A wild card domain name owning an SOA RRSet means that the domain A wild card domain name owning an SOA RRSet means that the
is at the root of the zone (apex). The domain can not be a source of domain is at the root of the zone (apex). The domain can not
synthesis because that is, by definition, a descendent node (of be a source of synthesis because that is, by definition, a
the closest encloser) and a zone apex is at the top of the zone. descendent node (of the closest encloser) and a zone apex is
at the top of the zone.
Although a wild card domain name owning an SOA RRSet can never be a Although a wild card domain name owning an SOA RRSet can never
source of synthesis, there is no reason to forbid the ownership of be a source of synthesis, there is no reason to forbid the
an SOA RRSet. ownership of an SOA RRSet.
E.g., given this zone: E.g., given this zone:
$ORIGIN *.example. $ORIGIN *.example.
@ 3600 IN SOA <SOA RDATA> @ 3600 IN SOA <SOA RDATA>
3600 NS ns1.example.com. 3600 NS ns1.example.com.
3600 NS ns1.example.net. 3600 NS ns1.example.net.
www 3600 TXT "the www txt record" www 3600 TXT "the www txt record"
A query for www.*.example.'s TXT record would still find the "the www A query for www.*.example.'s TXT record would still find the
txt record" answer. The reason is that the asterisk label only "the www txt record" answer. The reason is that the asterisk
becomes significant when RFC 1034's 4.3.2, step 3 part 'c' in in label only becomes significant when RFC 1034's 4.3.2, step 3
effect. part 'c' in in effect.
Of course, there would need to be a delegation in the parent zone, Of course, there would need to be a delegation in the parent
"example." for this to work too. This is covered in the next section. zone, "example." for this to work too. This is covered in the
next section.
4.2 NS RRSet at a Wild Card Domain Name 4.2 NS RRSet at a Wild Card Domain Name
With the definition of DNSSEC [RFC4033, RFC4034, RFC4035] now in With the definition of DNSSEC [RFC4033, RFC4034, RFC4035] now
place, the semantics of a wild card domain name owning an NS RR has in place, the semantics of a wild card domain name owning an
come to be poorly defined. The dilemma relates to a conflict NS RR has come to be poorly defined. The dilemma relates to
between the rules for synthesis in part 'c' and the fact that the a conflict between the rules for synthesis in part 'c' and the
resulting synthesis generates a record for which the zone is not fact that the resulting synthesis generates a record for which
authoritative. In a DNSSEC signed zone, the mechanics of signature the zone is not authoritative. In a DNSSEC signed zone, the
management (generation and inclusion in a message) become unclear. mechanics of signature management (generation and inclusion
in a message) become unclear.
After some lengthy discussions, there has been no clear "best answer" After some lengthy discussions, there has been no clear "best
on how to document the semantics of such a situation. Barring such answer" on how to document the semantics of such a situation.
records from the DNS would require definition of rules for that, as Barring such records from the DNS would require definition of
well as introducing a restriction on records that were once legal. rules for that, as well as introducing a restriction on records
Allowing such records and amending the process of signature that were once legal. Allowing such records and amending the
management would entail complicating the DNSSEC definition. process of signature management would entail complicating the
DNSSEC definition.
Combining these observations with thought that a wild card domain name Combining these observations with thought that a wild card
owning an NS record is an operationally uninteresting scenario, i.e., domain name owning an NS record is an operationally uninteresting
it won't happen in the normal course of events, accomodating this scenario, i.e., it won't happen in the normal course of events,
situation in the specification would also be categorized as accomodating this situation in the specification would also be
"needless complication." Further, expending more effort on this categorized as "needless complication." Further, expending more
topic has proven to be an exercise in diminishing returns. effort on this topic has proven to be an exercise in diminishing
returns.
In summary, there is no definition given for wild card domain names In summary, there is no definition given for wild card domain
owning an NS RRSet. The semantics are left undefined until there names owning an NS RRSet. The semantics are left undefined until
is a clear need to have a set defined, and until there is a clear there is a clear need to have a set defined, and until there is
direction to proceed. Operationally, inclusion of wild card NS a clear direction to proceed. Operationally, inclusion of wild
RRSets in a zone is discouraged, but not barred. card NS RRSets in a zone is discouraged, but not barred.
4.3 CNAME RRSet at a Wild Card Domain Name 4.3 CNAME RRSet at a Wild Card Domain Name
The issue of a CNAME RRSet owned by a wild card domain name has The issue of a CNAME RRSet owned by a wild card domain name has
prompted a suggested change to the last paragraph of step 3c of the prompted a suggested change to the last paragraph of step 3c of
algorithm in 4.3.2. The changed text appears in section 3.3.3 of the algorithm in 4.3.2. The changed text appears in section
this document. 3.3.3 of this document.
4.4 DNAME RRSet at a Wild Card Domain Name 4.4 DNAME RRSet at a Wild Card Domain Name
Ownership of a DNAME RRSet by a wild card domain name represents a Ownership of a DNAME RRSet by a wild card domain name
threat to the coherency of the DNS and is to be avoided or outright represents a threat to the coherency of the DNS and is to be
rejected. Such a DNAME RRSet represents non-deterministic synthesis avoided or outright rejected. Such a DNAME RRSet represents
of rules fed to different caches. As caches are fed the different non-deterministic synthesis of rules fed to different caches.
rules (in an unpredictable manner) the caches will cease to be As caches are fed the different rules (in an unpredictable
coherent. ("As caches are fed" refers to the storage in a cache of manner) the caches will cease to be coherent. ("As caches
records obtained in responses by recursive or iterative servers.) are fed" refers to the storage in a cache of records obtained
in responses by recursive or iterative servers.)
For example, assume one cache, responding to a recursive request, For example, assume one cache, responding to a recursive request,
obtains the record "a.b.example. DNAME foo.bar.tld." and another obtains the record "a.b.example. DNAME foo.bar.tld." and another
cache obtains "b.example. DNAME foo.bar.tld.", both generated from cache obtains "b.example. DNAME foo.bar.tld.", both generated
the record "*.example. DNAME foo.bar.tld." by an authoritative server. from the record "*.example. DNAME foo.bar.tld." by an
authoritative server.
The DNAME specification is not clear on whether DNAME records in a The DNAME specification is not clear on whether DNAME records
cache are used to rewrite queries. In some interpretations, the in a cache are used to rewrite queries. In some interpretations,
rewrite occurs, in some, it is not. Allowing for the occurrence of the rewrite occurs, in some, it is not. Allowing for the
rewriting, queries for "sub.a.b.example. A" may be rewritten as occurrence of rewriting, queries for "sub.a.b.example. A" may
"sub.foo.bar.tld. A" by the former caching server and may be rewritten be rewritten as "sub.foo.bar.tld. A" by the former caching
as "sub.a.foo.bar.tld. A" by the latter. Coherency is lost, an server and may be rewritten as "sub.a.foo.bar.tld. A" by the
operational nightmare ensues. latter. Coherency is lost, an operational nightmare ensues.
Another justification for banning or avoiding wildcard DNAME records Another justification for banning or avoiding wildcard DNAME
is the observation that such a record could synthesize a DNAME owned records is the observation that such a record could synthesize
by "sub.foo.bar.example." and "foo.bar.example." There is a a DNAME owned by "sub.foo.bar.example." and "foo.bar.example."
restriction in the DNAME definition that no domain exist below a There is a restriction in the DNAME definition that no domain
DNAME-owning domain, hence, the wildcard DNAME is not to be permitted. exist below a DNAME-owning domain, hence, the wildcard DNAME
is not to be permitted.
4.5 SRV RRSet at a Wild Card Domain Name 4.5 SRV RRSet at a Wild Card Domain Name
The definition of the SRV RRset is RFC 2782 [RFC2782]. In the The definition of the SRV RRset is RFC 2782 [RFC2782]. In the
definition of the record, there is some confusion over the term definition of the record, there is some confusion over the term
"Name." The definition reads as follows: "Name." The definition reads as follows:
# The format of the SRV RR # The format of the SRV RR
... ...
# _Service._Proto.Name TTL Class SRV Priority Weight Port Target # _Service._Proto.Name TTL Class SRV Priority Weight Port Target
... ...
# Name # Name
# The domain this RR refers to. The SRV RR is unique in that the # The domain this RR refers to. The SRV RR is unique in that the
# name one searches for is not this name; the example near the end # name one searches for is not this name; the example near the end
# shows this clearly. # shows this clearly.
Do not confuse the definition "Name" with a domain name. I.e., once Do not confuse the definition "Name" with a domain name. I.e.,
removing the _Service and _Proto labels from the owner name of the once removing the _Service and _Proto labels from the owner name
SRV RRSet, what remains could be a wild card domain name but this is of the SRV RRSet, what remains could be a wild card domain name
immaterial to the SRV RRSet. but this is immaterial to the SRV RRSet.
E.g., If an SRV record is: E.g., If an SRV record is:
_foo._udp.*.example. 10800 IN SRV 0 1 9 old-slow-box.example. _foo._udp.*.example. 10800 IN SRV 0 1 9 old-slow-box.example.
*.example is a wild card domain name and although it it the Name of *.example is a wild card domain name and although it it the Name
the SRV RR, it is not the owner (domain name). The owner domain name of the SRV RR, it is not the owner (domain name). The owner
is "_foo._udp.*.example." which is not a wild card domain name. domain name is "_foo._udp.*.example." which is not a wild card
domain name.
The confusion is likely based on the mixture of the specification of The confusion is likely based on the mixture of the specification
the SRV RR and the description of a "use case." of the SRV RR and the description of a "use case."
4.6 DS RRSet at a Wild Card Domain Name 4.6 DS RRSet at a Wild Card Domain Name
A DS RRSet owned by a wild card domain name is meaningless and A DS RRSet owned by a wild card domain name is meaningless and
harmless. harmless.
4.7 NSEC RRSet at a Wild Card Domain Name 4.7 NSEC RRSet at a Wild Card Domain Name
Wild card domain names in DNSSEC signed zones will have an NSEC RRSet. Wild card domain names in DNSSEC signed zones will have an NSEC
Synthesis of these records will only occur when the query exactly RRSet. Synthesis of these records will only occur when the
matches the record. Synthesized NSEC RR's will not be harmful as query exactly matches the record. Synthesized NSEC RR's will not
they will never be used in negative caching or to generate a negative be harmful as they will never be used in negative caching or to
response. generate a negative response.
4.8 RRSIG at a Wild Card Domain Name 4.8 RRSIG at a Wild Card Domain Name
RRSIG records will be present at a wild card domain name in a signed RRSIG records will be present at a wild card domain name in a
zone, and will be synthesized along with data sought in a query. signed zone, and will be synthesized along with data sought in a
The fact that the owner name is synthesized is not a problem as the query. The fact that the owner name is synthesized is not a
label count in the RRSIG will instruct the verifying code to ignore problem as the label count in the RRSIG will instruct the
it. verifying code to ignore it.
4.9 Empty Non-terminal Wild Card Domain Name 4.9 Empty Non-terminal Wild Card Domain Name
If a source of synthesis is an empty non-terminal, then the response If a source of synthesis is an empty non-terminal, then the
will be one of no error in the return code and no RRSet in the answer response will be one of no error in the return code and no RRSet
section. in the answer section.
5. Security Considerations 5. Security Considerations
This document is refining the specifications to make it more likely This document is refining the specifications to make it more
that security can be added to DNS. No functional additions are being likely that security can be added to DNS. No functional
made, just refining what is considered proper to allow the DNS, additions are being made, just refining what is considered
security of the DNS, and extending the DNS to be more predictable. proper to allow the DNS, security of the DNS, and extending
the DNS to be more predictable.
6. IANA Considerations 6. IANA Considerations
None. None.
7. References 7. References
Normative References Normative References
[RFC20] ASCII Format for Network Interchange, V.G. Cerf, Oct-16-1969 [RFC20] ASCII Format for Network Interchange, V.G. Cerf,
Oct-16-1969
[RFC1034] Domain Names - Concepts and Facilities, P.V. Mockapetris, [RFC1034] Domain Names - Concepts and Facilities,
Nov-01-1987 P.V. Mockapetris, Nov-01-1987
[RFC1035] Domain Names - Implementation and Specification, P.V [RFC1035] Domain Names - Implementation and Specification, P.V
Mockapetris, Nov-01-1987 Mockapetris, Nov-01-1987
[RFC1995] Incremental Zone Transfer in DNS, M. Ohta, August 1996 [RFC1995] Incremental Zone Transfer in DNS, M. Ohta, August 1996
[RFC2119] Key Words for Use in RFCs to Indicate Requirement Levels, S [RFC2119] Key Words for Use in RFCs to Indicate Requirement
Bradner, March 1997 Levels, S Bradner, March 1997
[RFC2181] Clarifications to the DNS Specification, R. Elz and R. Bush, [RFC2181] Clarifications to the DNS Specification, R. Elz and
July 1997 R. Bush, July 1997
[RFC2308] Negative Caching of DNS Queries (DNS NCACHE), M. Andrews, [RFC2308] Negative Caching of DNS Queries (DNS NCACHE),
March 1998 M. Andrews, March 1998
[RFC2782] A DNS RR for specifying the location of services (DNS SRV), [RFC2782] A DNS RR for specifying the location of services (DNS
A. Gulbrandsen, et.al., February 2000 SRV), A. Gulbrandsen, et.al., February 2000
[RFC4033] DNS Security Introduction and Requirements, R. Arends, [RFC4033] DNS Security Introduction and Requirements, R. Arends,
et.al., March 2005 et.al., March 2005
[RFC4034] Resource Records for the DNS Security Extensions, R. Arends, [RFC4034] Resource Records for the DNS Security Extensions,
et.al., March 2005 R. Arends, et.al., March 2005
[RFC4035] Protocol Modifications for the DNS Security Extensions, [RFC4035] Protocol Modifications for the DNS Security Extensions,
R. Arends, et.al., March 2005 R. Arends, et.al., March 2005
[RFC2672] Non-Terminal DNS Name Redirection, M. Crawford, August 1999 [RFC2672] Non-Terminal DNS Name Redirection, M. Crawford,
August 1999
Informative References Informative References
[RFC2136] Dynamic Updates in the Domain Name System (DNS UPDATE), P. [RFC2136] Dynamic Updates in the Domain Name System (DNS UPDATE),
Vixie, Ed., S. Thomson, Y. Rekhter, J. Bound, April 1997 P. Vixie, Ed., S. Thomson, Y. Rekhter, J. Bound,
April 1997
8. Editor 8. Editor
Name: Edward Lewis Name: Edward Lewis
Affiliation: NeuStar Affiliation: NeuStar
Address: 46000 Center Oak Plaza, Sterling, VA, 20166, US Address: 46000 Center Oak Plaza, Sterling, VA, 20166, US
Phone: +1-571-434-5468 Phone: +1-571-434-5468
Email: ed.lewis@neustar.biz Email: ed.lewis@neustar.biz
Comments on this document can be sent to the editor or the mailing Comments on this document can be sent to the editor or the mailing
skipping to change at line 786 skipping to change at line 821
editor merely recorded the collective wisdom of the working group. editor merely recorded the collective wisdom of the working group.
10. Trailing Boilerplate 10. Trailing Boilerplate
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
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INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
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and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the
such proprietary rights by implementers or users of this use of such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR
http://www.ietf.org/ipr. The IETF invites any interested party to repository at http://www.ietf.org/ipr. The IETF invites any
bring to its attention any copyrights, patents or patent interested party to bring to its attention any copyrights,
applications, or other proprietary rights that may cover technology patents or patent applications, or other proprietary rights
that may be required to implement this standard. Please address the that may cover technology that may be required to implement
information to the IETF at ietf-ipr@ietf.org. this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgement Acknowledgement
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
Expiration Expiration
This document expires on or about November 11, 2005. This document expires on or about November 16, 2005.
 End of changes. 

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