draft-ietf-dnsext-rfc2672bis-dname-12.txt   draft-ietf-dnsext-rfc2672bis-dname-13.txt 
DNS Extensions Working Group S. Rose DNS Extensions Working Group S. Rose
Internet-Draft NIST Internet-Draft NIST
Obsoletes: 2672 (if approved) W. Wijngaards Obsoletes: 2672 (if approved) W. Wijngaards
Updates: 3363,4294 NLnet Labs Updates: 3363,4294 NLnet Labs
(if approved) April 21, 2008 (if approved) May 2, 2008
Intended status: Standards Track Intended status: Standards Track
Expires: October 23, 2008 Expires: November 3, 2008
Update to DNAME Redirection in the DNS Update to DNAME Redirection in the DNS
draft-ietf-dnsext-rfc2672bis-dname-12 draft-ietf-dnsext-rfc2672bis-dname-13
Status of This Memo Status of This Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 1, line 37 skipping to change at page 1, line 37
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on October 23, 2008. This Internet-Draft will expire on November 3, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2008). Copyright (C) The IETF Trust (2008).
Abstract Abstract
The DNAME record provides redirection for a sub-tree of the domain The DNAME record provides redirection for a sub-tree of the domain
name tree in the DNS system. That is, all names that end with a name tree in the DNS system. That is, all names that end with a
particular suffix are redirected to another part of the DNS. This is particular suffix are redirected to another part of the DNS. This is
an update to the original specification in RFC 2672, also aligning an update of the original specification in RFC 2672, also aligning
RFC 3363 and RFC 4294 with this revision. RFC 3363 and RFC 4294 with this revision.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The DNAME Resource Record . . . . . . . . . . . . . . . . . . 3 2. The DNAME Resource Record . . . . . . . . . . . . . . . . . . 3
2.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. The DNAME Substitution . . . . . . . . . . . . . . . . . . 4 2.2. The DNAME Substitution . . . . . . . . . . . . . . . . . . 4
2.3. DNAME Apex not Redirected itself . . . . . . . . . . . . . 5 2.3. DNAME Apex not Redirected itself . . . . . . . . . . . . . 5
2.4. Names Next to and Below a DNAME Record . . . . . . . . . . 6 2.4. Names Next to and Below a DNAME Record . . . . . . . . . . 6
2.5. Compression of the DNAME record. . . . . . . . . . . . . . 6 2.5. Compression of the DNAME record. . . . . . . . . . . . . . 6
3. Processing . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. Processing . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Server algorithm . . . . . . . . . . . . . . . . . . . . . 7 3.1. CNAME synthesis and UD bit . . . . . . . . . . . . . . . . 7
3.2. Wildcards . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2. Server algorithm . . . . . . . . . . . . . . . . . . . . . 8
3.3. CNAME synthesis and UD bit . . . . . . . . . . . . . . . . 9 3.3. Wildcards . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4. Acceptance and Intermediate Storage . . . . . . . . . . . 10 3.4. Acceptance and Intermediate Storage . . . . . . . . . . . 10
4. DNAME Discussions in Other Documents . . . . . . . . . . . . . 10 4. DNAME Discussions in Other Documents . . . . . . . . . . . . . 10
5. Other Issues with DNAME . . . . . . . . . . . . . . . . . . . 12 5. Other Issues with DNAME . . . . . . . . . . . . . . . . . . . 12
5.1. Canonical hostnames cannot be below DNAME owners . . . . . 12 5.1. Canonical hostnames cannot be below DNAME owners . . . . . 12
5.2. Dynamic Update and DNAME . . . . . . . . . . . . . . . . . 12 5.2. Dynamic Update and DNAME . . . . . . . . . . . . . . . . . 12
5.3. DNSSEC and DNAME . . . . . . . . . . . . . . . . . . . . . 12 5.3. DNSSEC and DNAME . . . . . . . . . . . . . . . . . . . . . 12
5.3.1. DNAME bit in NSEC type map . . . . . . . . . . . . . . 12 5.3.1. DNAME bit in NSEC type map . . . . . . . . . . . . . . 12
5.3.2. Validators Must Understand DNAME . . . . . . . . . . . 12 5.3.2. Validators Must Understand DNAME . . . . . . . . . . . 12
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7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . . 15 9.2. Informative References . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
DNAME is a DNS Resource Record type defined in RFC 2672 [RFC2672]. DNAME is a DNS Resource Record type originally defined in RFC 2672
DNAME provides redirection from a part of the DNS name tree to [RFC2672]. DNAME provides redirection from a part of the DNS name
another part of the DNS name tree. tree to another part of the DNS name tree.
The DNAME RR and the CNAME RR [RFC1034] cause a lookup to The DNAME RR and the CNAME RR [RFC1034] cause a lookup to
(potentially) return data corresponding to a domain name different (potentially) return data corresponding to a domain name different
from the queried domain name. The difference between the two from the queried domain name. The difference between the two
resource records is that the CNAME RR directs the lookup of data at resource records is that the CNAME RR directs the lookup of data at
its owner to another single name, a DNAME RR directs lookups for data its owner to another single name, a DNAME RR directs lookups for data
at descendents of its owner's name to corresponding names under a at descendents of its owner's name to corresponding names under a
different (single) node of the tree. different (single) node of the tree.
Take for example, looking through a zone (see RFC 1034 [RFC1034], Take for example, looking through a zone (see RFC 1034 [RFC1034],
section 4.3.2, step 3) for the domain name "foo.example.com" and a section 4.3.2, step 3) for the domain name "foo.example.com" and a
DNAME resource record is found at "example.com" indicating that all DNAME resource record is found at "example.com" indicating that all
queries under "example.com" be directed to "example.net". The lookup queries under "example.com" be directed to "example.net". The lookup
process will return to step 1 with the new query name of process will return to step 1 with the new query name of
"foo.example.net". Had the query name been "www.foo.example.com" the "foo.example.net". Had the query name been "www.foo.example.com" the
new query name would be "www.foo.example.net". new query name would be "www.foo.example.net".
This document is an update to the original specification of DNAME in This document is an update of the original specification of DNAME in
RFC 2672 [RFC2672]. DNAME was conceived to help with the problem of RFC 2672 [RFC2672]. DNAME was conceived to help with the problem of
maintaining address-to-name mappings in a context of network maintaining address-to-name mappings in a context of network
renumbering. With a careful set-up, a renumbering event in the renumbering. With a careful set-up, a renumbering event in the
network causes no change to the authoritative server that has the network causes no change to the authoritative server that has the
address-to-name mappings. Examples in practice are classless reverse address-to-name mappings. Examples in practice are classless reverse
address space delegations and punycode alternates for domain spaces. address space delegations.
Another usage of DNAME lies in redirection of name spaces. For Another usage of DNAME lies in redirection of name spaces. For
example, a zone administrator may want sub-trees of the DNS to example, a zone administrator may want sub-trees of the DNS to
contain the same information. DNAME is also used for the redirection contain the same information. Examples include punycode alternates
of ENUM domains to another maintaining party. for domain spaces. DNAME is also used for the redirection of ENUM
domains to another maintaining party.
This update to DNAME does not change the wire format or the handling This update to DNAME does not change the wire format or the handling
of DNAME Resource Records by existing software. A new UD (Understand of DNAME Resource Records by existing software. A new UD (Understand
Dname) bit in the EDNS flags field can be used to signal that CNAME DNAME) bit in the EDNS flags field can be used to signal that CNAME
synthesis is not needed. Discussion is added on problems that may be synthesis is not needed. Discussion is added on problems that may be
encountered when using DNAME. encountered when using DNAME.
2. The DNAME Resource Record 2. The DNAME Resource Record
2.1. Format 2.1. Format
The DNAME RR has mnemonic DNAME and type code 39 (decimal). It is The DNAME RR has mnemonic DNAME and type code 39 (decimal). It is
not class-sensitive. not class-sensitive.
skipping to change at page 6, line 48 skipping to change at page 6, line 48
The DNAME owner name can be compressed like any other owner name. The DNAME owner name can be compressed like any other owner name.
The DNAME RDATA target name MUST NOT be sent out in compressed form, The DNAME RDATA target name MUST NOT be sent out in compressed form,
so that a DNAME RR can be treated as an unknown type [RFC3597]. so that a DNAME RR can be treated as an unknown type [RFC3597].
Although the previous DNAME specification [RFC2672] (that is Although the previous DNAME specification [RFC2672] (that is
obsoleted by this specification) talked about signaling to allow obsoleted by this specification) talked about signaling to allow
compression of the target name, such signaling is not specified. compression of the target name, such signaling is not specified.
RFC 2672 stated that the EDNS version had a meaning for understanding RFC 2672 stated that the EDNS version had a meaning for understanding
of DNAME and DNAME target name compression. This document updates of DNAME and DNAME target name compression. This document updates
RFC 2672, in that there is no EDNS version signaling for DNAME as of RFC 2672, in that there is no EDNS version signaling for DNAME.
yet. However, the flags section of EDNS(0) is updated with a However, the flags section of EDNS(0) is updated with a Understand-
Understand-DNAME flag by this document (See Section 3.3). DNAME flag by this document (See Section 3.3).
3. Processing 3. Processing
The DNAME RR causes type NS additional section processing. The DNAME RR causes type NS additional section processing.
3.1. Server algorithm 3.1. CNAME synthesis and UD bit
When preparing an response, a server upon performing a DNAME
substitution will in all cases include the DNAME RR used in the
answer section. A CNAME RR record with TTL equal to the
corresponding DNAME RR is synthesized and included in the answer
section for old resolvers. The owner name of the CNAME is the QNAME
of the query. DNSSEC [RFC4033], [RFC4034], [RFC4035] says that the
synthesized CNAME does not have to be signed. The DNAME has an RRSIG
and a validating resolver can check the CNAME against the DNAME
record and validate the DNAME record.
Resolvers MUST be able to handle a synthesized CNAME TTL of zero or
equal to the TTL of the corresponding DNAME record. A TTL of zero
means that the CNAME can be discarded immediately after processing
the answer. DNAME aware resolvers can set the Understand-DNAME (UD
bit) to receive a response with only the DNAME RR and no synthesized
CNAMEs.
The UD bit is part of the EDNS [RFC2671] extended RCODE and Flags
field. It is used to omit server processing, transmission and
resolver processing of unsigned synthesized CNAMEs. Resolvers can
set this in a query to request omission of the synthesized CNAMEs.
Servers copy the UD bit to the response, and can omit synthesized
CNAMEs from the answer. Older resolvers do not set the UD bit, and
older servers do not copy the UD bit to the answer, and will not omit
synthesized CNAMEs.
Updated EDNS extended RCODE and Flags field.
+0 (MSB) +1 (LSB)
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
0: | EXTENDED-RCODE | VERSION |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
2: |DO|UD| Z |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Servers MUST be able to answer a query for a synthesized CNAME. Like
other query types this invokes the DNAME, and synthesizes the CNAME
into the answer.
3.2. Server algorithm
Below the server algorithm, which appeared in RFC 2672 Section 4.1, Below the server algorithm, which appeared in RFC 2672 Section 4.1,
is expanded to handle the UD (Understand Dname) bit. is expanded to handle the UD (Understand DNAME) bit.
1. Set or clear the value of recursion available in the response 1. Set or clear the value of recursion available in the response
depending on whether the name server is willing to provide depending on whether the name server is willing to provide
recursive service. If recursive service is available and recursive service. If recursive service is available and
requested via the RD bit in the query, go to step 5, otherwise requested via the RD bit in the query, go to step 5, otherwise
step 2. step 2.
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.
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6. Using local data only, attempt to add other RRs which may be 6. Using local data only, attempt to add other RRs which may be
useful to the additional section of the query. Exit. useful to the additional section of the query. Exit.
Note that there will be at most one ancestor with a DNAME as Note that there will be at most one ancestor with a DNAME as
described in step 4 unless some zone's data is in violation of the described in step 4 unless some zone's data is in violation of the
no-descendants limitation in section 3. An implementation might take no-descendants limitation in section 3. An implementation might take
advantage of this limitation by stopping the search of step 3c or advantage of this limitation by stopping the search of step 3c or
step 4 when a DNAME record is encountered. step 4 when a DNAME record is encountered.
3.2. Wildcards 3.3. Wildcards
The use of DNAME in conjunction with wildcards is discouraged The use of DNAME in conjunction with wildcards is discouraged
[RFC4592]. Thus records of the form "*.example.com DNAME [RFC4592]. Thus records of the form "*.example.com DNAME
example.net" SHOULD NOT be used. example.net" SHOULD NOT be used.
The interaction between the expansion of the wildcard and the The interaction between the expansion of the wildcard and the
redirection of the DNAME is non-deterministic. Because the redirection of the DNAME is non-deterministic. Because the
processing is non-deterministic, DNSSEC validating resolvers may not processing is non-deterministic, DNSSEC validating resolvers may not
be able to validate a wildcarded DNAME. be able to validate a wildcarded DNAME.
A server MAY give a warning that the behavior is unspecified if such A server MAY give a warning that the behavior is unspecified if such
a wildcarded DNAME is loaded. The server MAY refuse it, refuse to a wildcarded DNAME is loaded. The server MAY refuse it, refuse to
load or refuse dynamic update. load or refuse dynamic update.
3.3. CNAME synthesis and UD bit
When preparing an response, a server upon performing a DNAME
substitution will in all cases include the DNAME RR used in the
answer section. A CNAME RR record with TTL equal to the
corresponding DNAME RR is synthesized and included in the answer
section for old resolvers. The owner name of the CNAME is the QNAME
of the query. DNSSEC [RFC4033], [RFC4034], [RFC4035] says that the
synthesized CNAME does not have to be signed. The DNAME has an RRSIG
and a validating resolver can check the CNAME against the DNAME
record and validate the DNAME record.
Resolvers MUST be able to handle a synthesized CNAME TTL of zero or
equal to the TTL of the corresponding DNAME record. A TTL of zero
means that the CNAME can be discarded immediately after processing
the answer. DNAME aware resolvers can set the Understand-DNAME (UD
bit) to receive a response with only the DNAME RR and no synthesized
CNAMEs.
The UD bit is part of the EDNS [RFC2671] extended RCODE and Flags
field. It is used to omit server processing, transmission and
resolver processing of unsigned synthesized CNAMEs. Resolvers can
set this in a query to request omission of the synthesized CNAMEs.
Servers copy the UD bit to the response, and can omit synthesized
CNAMEs from the answer. Older resolvers do not set the UD bit, and
older servers do not copy the UD bit to the answer, and will not omit
synthesized CNAMEs.
Updated EDNS extended RCODE and Flags field.
+0 (MSB) +1 (LSB)
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
0: | EXTENDED-RCODE | VERSION |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
2: |DO|UD| Z |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Servers MUST be able to answer a query for a synthesized CNAME. Like
other query types this invokes the DNAME, and synthesizes the CNAME
into the answer.
3.4. Acceptance and Intermediate Storage 3.4. Acceptance and Intermediate Storage
DNS caches can encounter data at names below the owner name of a DNS caches can encounter data at names below the owner name of a
DNAME RR, due to a change at the authoritative server where data from DNAME RR, due to a change at the authoritative server where data from
before and after the change resides in the cache. This conflict before and after the change resides in the cache. This conflict
situation is a transitional phase, that ends when the old data times situation is a transitional phase, that ends when the old data times
out. The cache can opt to store both old and new data and treat each out. The cache can opt to store both old and new data and treat each
as if the other did not exist, or drop the old data, or drop the as if the other did not exist, or drop the old data, or drop the
longer domain name. In any approach, consistency returns after the longer domain name. In any approach, consistency returns after the
older data TTL times out. older data TTL times out.
DNS caches MUST perform CNAME synthesis on behalf of DNAME-ignorant DNS caches MUST perform CNAME synthesis on behalf of DNAME-ignorant
clients. A DNS cache that understands DNAMEs can send out queries on clients. A DNS cache that understands DNAMEs can send out queries on
behalf of clients with the UD bit set. After receiving the answers behalf of clients with the UD bit set (See Section 3.1). After
the DNS cache sends replies to DNAME ignorant clients that include receiving the answers the DNS cache sends replies to DNAME ignorant
DNAMEs and synthesized CNAMEs. clients that include DNAMEs and synthesized CNAMEs.
4. DNAME Discussions in Other Documents 4. DNAME Discussions in Other Documents
In [RFC2181], in Section 10.3., the discussion on MX and NS records In [RFC2181], in Section 10.3., the discussion on MX and NS records
touches on redirection by CNAMEs, but this also holds for DNAMEs. touches on redirection by CNAMEs, but this also holds for DNAMEs.
Excerpt from 10.3. MX and NS records (in RFC 2181). Excerpt from 10.3. MX and NS records (in RFC 2181).
The domain name used as the value of a NS resource record, The domain name used as the value of a NS resource record,
or part of the value of a MX resource record must not be or part of the value of a MX resource record must not be
skipping to change at page 14, line 37 skipping to change at page 14, line 37
A validating resolver MUST understand DNAME, according to [RFC4034]. A validating resolver MUST understand DNAME, according to [RFC4034].
In Section 5.3.2 examples are given that illustrate this need. In Section 5.3.2 examples are given that illustrate this need.
8. Acknowledgments 8. Acknowledgments
The authors of this draft would like to acknowledge Matt Larson for The authors of this draft would like to acknowledge Matt Larson for
beginning this effort to address the issues related to the DNAME RR beginning this effort to address the issues related to the DNAME RR
type. The authors would also like to acknowledge Paul Vixie, Ed type. The authors would also like to acknowledge Paul Vixie, Ed
Lewis, Mark Andrews, Mike StJohns, Niall O'Reilly, Sam Weiler, Alfred Lewis, Mark Andrews, Mike StJohns, Niall O'Reilly, Sam Weiler, Alfred
Hoenes and Kevin Darcy for their review and comments on this Hines and Kevin Darcy for their review and comments on this document.
document.
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", [RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987. STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
skipping to change at page 15, line 15 skipping to change at page 15, line 15
[RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound, [RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)", "Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, April 1997. RFC 2136, April 1997.
[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS
Specification", RFC 2181, July 1997. Specification", RFC 2181, July 1997.
[RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)",
RFC 2671, August 1999. RFC 2671, August 1999.
[RFC2672] Crawford, M., "Non-Terminal DNS Name Redirection",
RFC 2672, August 1999.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782, specifying the location of services (DNS SRV)", RFC 2782,
February 2000. February 2000.
[RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record [RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record
(RR) Types", RFC 3597, September 2003. (RR) Types", RFC 3597, September 2003.
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements", Rose, "DNS Security Introduction and Requirements",
RFC 4033, March 2005. RFC 4033, March 2005.
skipping to change at page 15, line 45 skipping to change at page 15, line 42
Extensions", RFC 4035, March 2005. Extensions", RFC 4035, March 2005.
[RFC4592] Lewis, E., "The Role of Wildcards in the Domain Name [RFC4592] Lewis, E., "The Role of Wildcards in the Domain Name
System", RFC 4592, July 2006. System", RFC 4592, July 2006.
9.2. Informative References 9.2. Informative References
[RFC1912] Barr, D., "Common DNS Operational and Configuration [RFC1912] Barr, D., "Common DNS Operational and Configuration
Errors", RFC 1912, February 1996. Errors", RFC 1912, February 1996.
[RFC2672] Crawford, M., "Non-Terminal DNS Name Redirection",
RFC 2672, August 1999.
[RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. [RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T.
Hain, "Representing Internet Protocol version 6 (IPv6) Hain, "Representing Internet Protocol version 6 (IPv6)
Addresses in the Domain Name System (DNS)", RFC 3363, Addresses in the Domain Name System (DNS)", RFC 3363,
August 2002. August 2002.
[RFC4294] Loughney, J., "IPv6 Node Requirements", RFC 4294, [RFC4294] Loughney, J., "IPv6 Node Requirements", RFC 4294,
April 2006. April 2006.
Authors' Addresses Authors' Addresses
 End of changes. 20 change blocks. 
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