draft-ietf-6man-rdnss-rfc6106bis-02.txt   draft-ietf-6man-rdnss-rfc6106bis-03.txt 
Network Working Group J. Jeong Network Working Group J. Jeong
Internet-Draft Sungkyunkwan Univ./ETRI Internet-Draft Sungkyunkwan Univ./ETRI
Obsoletes: 6106 (if approved) S. Park Obsoletes: 6106 (if approved) S. Park
Intended status: Standards Track SAMSUNG Electronics Intended status: Standards Track SAMSUNG Electronics
Expires: February 12, 2016 L. Beloeil Expires: April 7, 2016 L. Beloeil
France Telecom R&D France Telecom R&D
S. Madanapalli S. Madanapalli
iRam Technologies iRam Technologies
August 11, 2015 October 5, 2015
IPv6 Router Advertisement Options for DNS Configuration IPv6 Router Advertisement Options for DNS Configuration
draft-ietf-6man-rdnss-rfc6106bis-02 draft-ietf-6man-rdnss-rfc6106bis-03
Abstract Abstract
This document specifies IPv6 Router Advertisement options to allow This document specifies IPv6 Router Advertisement options to allow
IPv6 routers to advertise a list of DNS recursive server addresses IPv6 routers to advertise a list of DNS recursive server addresses
and a DNS Search List to IPv6 hosts. and a DNS Search List to IPv6 hosts.
This document obsoletes RFC 6106 and allows a higher default value of This document obsoletes RFC 6106 and allows a higher default value of
the lifetime of the RA DNS options to avoid the frequent expiry of the lifetime of the RA DNS options to avoid the frequent expiry of
the options on links with a relatively high rate of packet loss. the options on links with a relatively high rate of packet loss.
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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."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on February 12, 2016. This Internet-Draft will expire on April 7, 2016.
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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Applicability Statements . . . . . . . . . . . . . . . . . 3 1.1. Applicability Statements . . . . . . . . . . . . . . . . . 3
1.2. Coexistence of RA Options and DHCP Options for DNS 1.2. Coexistence of RA Options and DHCP Options for DNS
Configuration . . . . . . . . . . . . . . . . . . . . . . 4 Configuration . . . . . . . . . . . . . . . . . . . . . . 4
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Neighbor Discovery Extension . . . . . . . . . . . . . . . . . 5 5. Neighbor Discovery Extension . . . . . . . . . . . . . . . . . 5
5.1. Recursive DNS Server Option . . . . . . . . . . . . . . . 5 5.1. Recursive DNS Server Option . . . . . . . . . . . . . . . 5
5.2. DNS Search List Option . . . . . . . . . . . . . . . . . . 6 5.2. DNS Search List Option . . . . . . . . . . . . . . . . . . 7
5.3. Procedure of DNS Configuration . . . . . . . . . . . . . . 8 5.3. Procedure of DNS Configuration . . . . . . . . . . . . . . 8
5.3.1. Procedure in IPv6 Host . . . . . . . . . . . . . . . . 8 5.3.1. Procedure in IPv6 Host . . . . . . . . . . . . . . . . 8
5.3.2. Warnings for DNS Options Configuration . . . . . . . . 9 5.3.2. Warnings for DNS Options Configuration . . . . . . . . 9
6. Implementation Considerations . . . . . . . . . . . . . . . . 9 6. Implementation Considerations . . . . . . . . . . . . . . . . 9
6.1. DNS Repository Management . . . . . . . . . . . . . . . . 9 6.1. DNS Repository Management . . . . . . . . . . . . . . . . 10
6.2. Synchronization between DNS Server List and Resolver 6.2. Synchronization between DNS Server List and Resolver
Repository . . . . . . . . . . . . . . . . . . . . . . . . 10 Repository . . . . . . . . . . . . . . . . . . . . . . . . 10
6.3. Synchronization between DNS Search List and Resolver 6.3. Synchronization between DNS Search List and Resolver
Repository . . . . . . . . . . . . . . . . . . . . . . . . 11 Repository . . . . . . . . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7.1. Security Threats . . . . . . . . . . . . . . . . . . . . . 12 7.1. Security Threats . . . . . . . . . . . . . . . . . . . . . 13
7.2. Recommendations . . . . . . . . . . . . . . . . . . . . . 13 7.2. Recommendations . . . . . . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . . 14 10.1. Normative References . . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . . 15 10.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. Changes from RFC 5006 . . . . . . . . . . . . . . . . 16 Appendix A. Changes from RFC 5006 . . . . . . . . . . . . . . . . 16
Appendix B. Changes from RFC 6106 . . . . . . . . . . . . . . . . 16 Appendix B. Changes from RFC 6106 . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
The purpose of this document is to standardize an IPv6 Router The purpose of this document is to standardize an IPv6 Router
Advertisement (RA) option for DNS Recursive Server Addresses used for Advertisement (RA) option for DNS Recursive Server Addresses used for
the DNS name resolution in IPv6 hosts. This RA option was specified the DNS name resolution in IPv6 hosts. This RA option was specified
in an earlier Experimental specification [RFC5006]. This document is in an earlier Experimental specification [RFC5006]. This document is
also to define a new RA option for Domain Name Search Lists for an also to define a new RA option for Domain Name Search Lists for an
enhanced DNS configuration. Thus, this document obsoletes [RFC5006], enhanced DNS configuration. Thus, this document obsoletes [RFC5006],
which only defines the RA option for DNS Recursive Server Addresses. which only defines the RA option for DNS Recursive Server Addresses.
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in [RFC4861]. A value of all one bits (0xffffffff) in [RFC4861]. A value of all one bits (0xffffffff)
represents infinity. A value of zero means that the represents infinity. A value of zero means that the
RDNSS address MUST no longer be used. RDNSS address MUST no longer be used.
Addresses of IPv6 Recursive DNS Servers Addresses of IPv6 Recursive DNS Servers
One or more 128-bit IPv6 addresses of the recursive One or more 128-bit IPv6 addresses of the recursive
DNS servers. The number of addresses is determined DNS servers. The number of addresses is determined
by the Length field. That is, the number of by the Length field. That is, the number of
addresses is equal to (Length - 1) / 2. addresses is equal to (Length - 1) / 2.
Note: The addresses for recursive DNS servers in the RDNSS option
MAY be link-local addresses. Such link-local addresses SHOULD be
registered into the resolver repository along with the
corresponding interfaces (or zones) that received the RDNSS
option(s) for them. The interface names (or zone indices) SHOULD
be represented in the textual format for scoped addresses in
described in [RFC4007]. When a resolver sends a DNS query message
to an RDNSS with a link-local address, it MUST use the
corresponding interface.
5.2. DNS Search List Option 5.2. DNS Search List Option
The DNSSL option contains one or more domain names of DNS suffixes. The DNSSL option contains one or more domain names of DNS suffixes.
All of the domain names share the same Lifetime value. If it is All of the domain names share the same Lifetime value. If it is
desirable to have different Lifetime values, multiple DNSSL options desirable to have different Lifetime values, multiple DNSSL options
can be used. Figure 2 shows the format of the DNSSL option. can be used. Figure 2 shows the format of the DNSSL option.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Soliman, "Neighbor Discovery for IP version 6 Soliman, "Neighbor Discovery for IP version 6
(IPv6)", RFC 4861, September 2007. (IPv6)", RFC 4861, September 2007.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6
Stateless Address Autoconfiguration", RFC 4862, Stateless Address Autoconfiguration", RFC 4862,
September 2007. September 2007.
[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.
[RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E.,
and B. Zill, "IPv6 Scoped Address Architecture",
RFC 4007, March 2005.
10.2. Informative References 10.2. Informative References
[RFC1034] Mockapetris, P., "Domain names - concepts and [RFC1034] Mockapetris, P., "Domain names - concepts and
facilities", STD 13, RFC 1034, November 1987. facilities", STD 13, RFC 1034, November 1987.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration C., and M. Carney, "Dynamic Host Configuration
Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3736] Droms, R., "Stateless Dynamic Host Configuration [RFC3736] Droms, R., "Stateless Dynamic Host Configuration
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high rate of packet loss. This revision relaxes the upper bound high rate of packet loss. This revision relaxes the upper bound
and sets a higher default value to avoid this problem. and sets a higher default value to avoid this problem.
o The lifetimes of RDNSS and DNSSL options are decoupled from Router o The lifetimes of RDNSS and DNSSL options are decoupled from Router
Lifetime. An RA router lifetime of zero does not cause the RDNSS Lifetime. An RA router lifetime of zero does not cause the RDNSS
and DNSSL options to be considered invalid because these options and DNSSL options to be considered invalid because these options
have their own lifetime values. Thus, due to the expiry of the RA have their own lifetime values. Thus, due to the expiry of the RA
router lifetime, the lists in the RDNSS and DNSSL options are not router lifetime, the lists in the RDNSS and DNSSL options are not
guaranteed to be reachable at any point in time. guaranteed to be reachable at any point in time.
o The addresses for recursive DNS servers in the RDNSS option can be
not only global addresses, but also link-local addresses. The
link-local addresses for RDNSSes should be specified in the
resolver repository along with the corresponding interface names
(or zone indices).
o The recommendation that at most three RDNSS addresses to maintain o The recommendation that at most three RDNSS addresses to maintain
by RDNSS options should be limited is removed. By this removal, by RDNSS options should be limited is removed. By this removal,
the number of RDNSSes to maintain is up to an implementer's local the number of RDNSSes to maintain is up to an implementer's local
policy. policy.
o The recommendation that at most three DNS domains to maintain by o The recommendation that at most three DNS domains to maintain by
DNSSL options should be limited is removed. By this removal, when DNSSL options should be limited is removed. By this removal, when
the set of unique DNSSL values are not equivalent, none of them the set of unique DNSSL values are not equivalent, none of them
are ignored for hostname lookups. are ignored for hostname lookups.
 End of changes. 12 change blocks. 
11 lines changed or deleted 31 lines changed or added

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