DNS Configuration options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
RFC 3646

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Network Working Group                                      R. Droms, Ed.
Request for Comments: 3646                                 Cisco Systems
Category: Standards Track                                  December 2003

              DNS Configuration options for Dynamic Host
                Configuration Protocol for IPv6 (DHCPv6)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document describes Dynamic Host Configuration Protocol for IPv6
   (DHCPv6) options for passing a list of available DNS recursive name
   servers and a domain search list to a client.

1.  Introduction

   This document describes two options for passing configuration
   information related to Domain Name Service (DNS) (RFC 1034 [6] and
   RFC 1035 [1]) in DHCPv6 (RFC 3315 [2]).

2.  Terminology

   The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be
   interpreted as described in BCP 14, RFC 2119 [3].

   Throughout this document, unless otherwise specified, the acronym
   DHCP refers to DHCP for IPv6 (DHCPv6) as specified in RFC 3315.

   This document uses terminology specific to IPv6 and DHCP as defined
   in section "Terminology" of RFC 3315.

Droms                       Standards Track                     [Page 1]
RFC 3646          DNS Configuration Options for DHCPv6     December 2003

3.  DNS Recursive Name Server option

   The DNS Recursive Name Server option provides a list of one or more
   IPv6 addresses of DNS recursive name servers to which a client's DNS
   resolver MAY send DNS queries [1].  The DNS servers are listed in the
   order of preference for use by the client resolver.

   The format of the DNS Recursive Name Server option is:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      OPTION_DNS_SERVERS       |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |            DNS-recursive-name-server (IPv6 address)           |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |            DNS-recursive-name-server (IPv6 address)           |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   option-code:               OPTION_DNS_SERVERS (23)

   option-len:                Length of the list of DNS recursive name
                              servers in octets; must be a multiple of
                              16

   DNS-recursive-name-server: IPv6 address of DNS recursive name server

4.  Domain Search List option

   The Domain Search List option specifies the domain search list the
   client is to use when resolving hostnames with DNS.  This option does
   not apply to other name resolution mechanisms.

Droms                       Standards Track                     [Page 2]
RFC 3646          DNS Configuration Options for DHCPv6     December 2003

   The format of the Domain Search List option is:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      OPTION_DOMAIN_LIST       |         option-len            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          searchlist                           |
      |                              ...                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   option-code:  OPTION_DOMAIN_LIST (24)

   option-len:   Length of the 'searchlist' field in octets

   searchlist:   The specification of the list of domain names in the
                 Domain Search List

   The list of domain names in the 'searchlist' MUST be encoded as
   specified in section "Representation and use of domain names" of RFC