<pre>Internet Engineering Task Force (IETF)                     E. Jankiewicz
Request for Comments: 6434                       SRI International, Inc.
Obsoletes: <a href="./rfc4294">4294</a>                                              J. Loughney
Category: Informational                                            Nokia
ISSN: 2070-1721                                                T. Narten
                                                         IBM Corporation
                                                           December 2011


                         <span class="h1">IPv6 Node Requirements</span>

Abstract

   This document defines requirements for IPv6 nodes.  It is expected
   that IPv6 will be deployed in a wide range of devices and situations.
   Specifying the requirements for IPv6 nodes allows IPv6 to function
   well and interoperate in a large number of situations and
   deployments.

   This document obsoletes <a href="./rfc4294">RFC 4294</a>.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see <a href="./rfc5741#section-2">Section&nbsp;2 of RFC 5741</a>.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   <a href="http://www.rfc-editor.org/info/rfc6434">http://www.rfc-editor.org/info/rfc6434</a>.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must



<span class="grey">Jankiewicz, et al.            Informational                     [Page 1]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-2" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   <a href="#section-1">1</a>.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  <a href="#page-4">4</a>
     <a href="#section-1.1">1.1</a>.  Scope of This Document . . . . . . . . . . . . . . . . . .  <a href="#page-5">5</a>
     <a href="#section-1.2">1.2</a>.  Description of IPv6 Nodes  . . . . . . . . . . . . . . . .  <a href="#page-5">5</a>
   <a href="#section-2">2</a>.  Requirements Language  . . . . . . . . . . . . . . . . . . . .  <a href="#page-5">5</a>
   <a href="#section-3">3</a>.  Abbreviations Used in This Document  . . . . . . . . . . . . .  <a href="#page-5">5</a>
   <a href="#section-4">4</a>.  Sub-IP Layer . . . . . . . . . . . . . . . . . . . . . . . . .  <a href="#page-6">6</a>
   <a href="#section-5">5</a>.  IP Layer . . . . . . . . . . . . . . . . . . . . . . . . . . .  <a href="#page-7">7</a>
     <a href="#section-5.1">5.1</a>.  Internet Protocol Version 6 - <a href="./rfc2460">RFC 2460</a> . . . . . . . . . .  <a href="#page-7">7</a>
     <a href="#section-5.2">5.2</a>.  Neighbor Discovery for IPv6 - <a href="./rfc4861">RFC 4861</a> . . . . . . . . . .  <a href="#page-8">8</a>
     5.3.  Default Router Preferences and More-Specific Routes -
           <a href="./rfc4191">RFC 4191</a> . . . . . . . . . . . . . . . . . . . . . . . . .  <a href="#page-9">9</a>
     <a href="#section-5.4">5.4</a>.  SEcure Neighbor Discovery (SEND) - <a href="./rfc3971">RFC 3971</a>  . . . . . . .  <a href="#page-9">9</a>
     <a href="#section-5.5">5.5</a>.  IPv6 Router Advertisement Flags Option - <a href="./rfc5175">RFC 5175</a>  . . . .  <a href="#page-9">9</a>
     <a href="#section-5.6">5.6</a>.  Path MTU Discovery and Packet Size . . . . . . . . . . . . <a href="#page-10">10</a>
       <a href="#section-5.6.1">5.6.1</a>.  Path MTU Discovery - <a href="./rfc1981">RFC 1981</a>  . . . . . . . . . . . . <a href="#page-10">10</a>
     <a href="#section-5.7">5.7</a>.  IPv6 Jumbograms - <a href="./rfc2675">RFC 2675</a> . . . . . . . . . . . . . . . . <a href="#page-10">10</a>
     5.8.  ICMP for the Internet Protocol Version 6 (IPv6) - <a href="./rfc4443">RFC</a>
           <a href="./rfc4443">4443</a> . . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-10">10</a>
     <a href="#section-5.9">5.9</a>.  Addressing . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-11">11</a>
       <a href="#section-5.9.1">5.9.1</a>.  IP Version 6 Addressing Architecture - <a href="./rfc4291">RFC 4291</a>  . . . <a href="#page-11">11</a>
       5.9.2.  IPv6 Stateless Address Autoconfiguration - <a href="./rfc4862">RFC 4862</a>  . 11
       5.9.3.  Privacy Extensions for Address Configuration in
               IPv6 - <a href="./rfc4941">RFC 4941</a>  . . . . . . . . . . . . . . . . . . . <a href="#page-12">12</a>
       <a href="#section-5.9.4">5.9.4</a>.  Default Address Selection for IPv6 - <a href="./rfc3484">RFC 3484</a>  . . . . <a href="#page-12">12</a>
       5.9.5.  Stateful Address Autoconfiguration (DHCPv6) - <a href="./rfc3315">RFC</a>
               <a href="./rfc3315">3315</a> . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-12">12</a>
     <a href="#section-5.10">5.10</a>. Multicast Listener Discovery (MLD) for IPv6  . . . . . . . <a href="#page-13">13</a>
   6.  DHCP versus Router Advertisement Options for Host
       Configuration  . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-13">13</a>
   <a href="#section-7">7</a>.  DNS and DHCP . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-14">14</a>



<span class="grey">Jankiewicz, et al.            Informational                     [Page 2]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-3" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


     <a href="#section-7.1">7.1</a>.  DNS  . . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-14">14</a>
     7.2.  Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
           - <a href="./rfc3315">RFC 3315</a> . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-15">15</a>
       <a href="#section-7.2.1">7.2.1</a>.  Other Configuration Information  . . . . . . . . . . . <a href="#page-15">15</a>
       7.2.2.  Use of Router Advertisements in Managed
               Environments . . . . . . . . . . . . . . . . . . . . . <a href="#page-15">15</a>
     7.3.  IPv6 Router Advertisement Options for DNS
           Configuration - <a href="./rfc6106">RFC 6106</a> . . . . . . . . . . . . . . . . . <a href="#page-15">15</a>
   <a href="#section-8">8</a>.  IPv4 Support and Transition  . . . . . . . . . . . . . . . . . <a href="#page-16">16</a>
     <a href="#section-8.1">8.1</a>.  Transition Mechanisms  . . . . . . . . . . . . . . . . . . <a href="#page-16">16</a>
       8.1.1.  Basic Transition Mechanisms for IPv6 Hosts and
               Routers - <a href="./rfc4213">RFC 4213</a> . . . . . . . . . . . . . . . . . . <a href="#page-16">16</a>
   <a href="#section-9">9</a>.  Application Support  . . . . . . . . . . . . . . . . . . . . . <a href="#page-16">16</a>
     <a href="#section-9.1">9.1</a>.  Textual Representation of IPv6 Addresses - <a href="./rfc5952">RFC 5952</a>  . . . <a href="#page-16">16</a>
     <a href="#section-9.2">9.2</a>.  Application Programming Interfaces (APIs)  . . . . . . . . <a href="#page-16">16</a>
   <a href="#section-10">10</a>. Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-17">17</a>
   <a href="#section-11">11</a>. Security . . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-17">17</a>
     <a href="#section-11.1">11.1</a>. Requirements . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-18">18</a>
     <a href="#section-11.2">11.2</a>. Transforms and Algorithms  . . . . . . . . . . . . . . . . <a href="#page-19">19</a>
   <a href="#section-12">12</a>. Router-Specific Functionality  . . . . . . . . . . . . . . . . <a href="#page-19">19</a>
     <a href="#section-12.1">12.1</a>. IPv6 Router Alert Option - <a href="./rfc2711">RFC 2711</a>  . . . . . . . . . . . <a href="#page-19">19</a>
     <a href="#section-12.2">12.2</a>. Neighbor Discovery for IPv6 - <a href="./rfc4861">RFC 4861</a> . . . . . . . . . . <a href="#page-19">19</a>
     <a href="#section-12.3">12.3</a>. Stateful Address Autoconfiguration (DHCPv6) - <a href="./rfc3315">RFC 3315</a> . . <a href="#page-19">19</a>
   <a href="#section-13">13</a>. Network Management . . . . . . . . . . . . . . . . . . . . . . <a href="#page-20">20</a>
     <a href="#section-13.1">13.1</a>. Management Information Base (MIB) Modules  . . . . . . . . <a href="#page-20">20</a>
       <a href="#section-13.1.1">13.1.1</a>. IP Forwarding Table MIB  . . . . . . . . . . . . . . . <a href="#page-20">20</a>
       13.1.2. Management Information Base for the Internet
               Protocol (IP)  . . . . . . . . . . . . . . . . . . . . <a href="#page-20">20</a>
   <a href="#section-14">14</a>. Security Considerations  . . . . . . . . . . . . . . . . . . . <a href="#page-20">20</a>
   <a href="#section-15">15</a>. Authors and Acknowledgments  . . . . . . . . . . . . . . . . . <a href="#page-21">21</a>
     <a href="#section-15.1">15.1</a>. Authors and Acknowledgments (Current Document) . . . . . . <a href="#page-21">21</a>
     <a href="#section-15.2">15.2</a>. Authors and Acknowledgments from <a href="./rfc4279">RFC 4279</a>  . . . . . . . . <a href="#page-21">21</a>
   <a href="#section-16">16</a>. Appendix: Changes from <a href="./rfc4294">RFC 4294</a>  . . . . . . . . . . . . . . . <a href="#page-22">22</a>
   <a href="#section-17">17</a>. References . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-23">23</a>
     <a href="#section-17.1">17.1</a>. Normative References . . . . . . . . . . . . . . . . . . . <a href="#page-23">23</a>
     <a href="#section-17.2">17.2</a>. Informative References . . . . . . . . . . . . . . . . . . <a href="#page-26">26</a>















<span class="grey">Jankiewicz, et al.            Informational                     [Page 3]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-4" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>.  Introduction</span>

   This document defines common functionality required from both IPv6
   hosts and routers.  Many IPv6 nodes will implement optional or
   additional features, but this document collects and summarizes
   requirements from other published Standards Track documents in one
   place.

   This document tries to avoid discussion of protocol details and
   references RFCs for this purpose.  This document is intended to be an
   applicability statement and to provide guidance as to which IPv6
   specifications should be implemented in the general case and which
   specifications may be of interest to specific deployment scenarios.
   This document does not update any individual protocol document RFCs.

   Although this document points to different specifications, it should
   be noted that in many cases, the granularity of a particular
   requirement will be smaller than a single specification, as many
   specifications define multiple, independent pieces, some of which may
   not be mandatory.  In addition, most specifications define both
   client and server behavior in the same specification, while many
   implementations will be focused on only one of those roles.

   This document defines a minimal level of requirement needed for a
   device to provide useful internet service and considers a broad range
   of device types and deployment scenarios.  Because of the wide range
   of deployment scenarios, the minimal requirements specified in this
   document may not be sufficient for all deployment scenarios.  It is
   perfectly reasonable (and indeed expected) for other profiles to
   define additional or stricter requirements appropriate for specific
   usage and deployment environments.  For example, this document does
   not mandate that all clients support DHCP, but some deployment
   scenarios may deem it appropriate to make such a requirement.  For
   example, government agencies in the USA have defined profiles for
   specialized requirements for IPv6 in target environments (see [<a href="#ref-DODv6" title="&quot;DoD IPv6 Standard Profiles For IPv6 Capable Products Version 5.0&quot;">DODv6</a>]
   and [<a href="#ref-USGv6" title="&quot;A Profile for IPv6 in the U.S. Government - Version 1.0&quot;">USGv6</a>]).

   As it is not always possible for an implementer to know the exact
   usage of IPv6 in a node, an overriding requirement for IPv6 nodes is
   that they should adhere to Jon Postel's Robustness Principle: "Be
   conservative in what you do, be liberal in what you accept from
   others" [<a href="./rfc0793" title="&quot;Transmission Control Protocol&quot;">RFC0793</a>].









<span class="grey">Jankiewicz, et al.            Informational                     [Page 4]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-5" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h3"><a class="selflink" id="section-1.1" href="#section-1.1">1.1</a>.  Scope of This Document</span>

   IPv6 covers many specifications.  It is intended that IPv6 will be
   deployed in many different situations and environments.  Therefore,
   it is important to develop requirements for IPv6 nodes to ensure
   interoperability.

   This document assumes that all IPv6 nodes meet the minimum
   requirements specified here.

<span class="h3"><a class="selflink" id="section-1.2" href="#section-1.2">1.2</a>.  Description of IPv6 Nodes</span>

   From the Internet Protocol, Version 6 (IPv6) Specification [<a href="./rfc2460" title="&quot;Internet Protocol, Version 6 (IPv6) Specification&quot;">RFC2460</a>],
   we have the following definitions:

   IPv6 node   - a device that implements IPv6.

   IPv6 router - a node that forwards IPv6 packets not explicitly
                 addressed to itself.

   IPv6 host   - any node that is not a router.

<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>.  Requirements Language</span>

   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 <a href="./rfc2119">RFC 2119</a> [<a href="./rfc2119" title="&quot;Key words for use in RFCs to Indicate Requirement Levels&quot;">RFC2119</a>].

<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>.  Abbreviations Used in This Document</span>

   ATM   Asynchronous Transfer Mode

   AH    Authentication Header

   DAD   Duplicate Address Detection

   ESP   Encapsulating Security Payload

   ICMP  Internet Control Message Protocol

   IKE   Internet Key Exchange

   MIB   Management Information Base

   MLD   Multicast Listener Discovery

   MTU   Maximum Transmission Unit




<span class="grey">Jankiewicz, et al.            Informational                     [Page 5]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-6" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   NA    Neighbor Advertisement

   NBMA  Non-Broadcast Multiple Access

   ND    Neighbor Discovery

   NS    Neighbor Solicitation

   NUD   Neighbor Unreachability Detection

   PPP   Point-to-Point Protocol

<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>.  Sub-IP Layer</span>

   An IPv6 node must include support for one or more IPv6 link-layer
   specifications.  Which link-layer specifications an implementation
   should include will depend upon what link-layers are supported by the
   hardware available on the system.  It is possible for a conformant
   IPv6 node to support IPv6 on some of its interfaces and not on
   others.

   As IPv6 is run over new layer 2 technologies, it is expected that new
   specifications will be issued.  In the following, we list some of the
   layer 2 technologies for which an IPv6 specification has been
   developed.  It is provided for informational purposes only and may
   not be complete.

   -  Transmission of IPv6 Packets over Ethernet Networks [<a href="./rfc2464" title="&quot;Transmission of IPv6 Packets over Ethernet Networks&quot;">RFC2464</a>]

   -  IPv6 over ATM Networks [<a href="./rfc2492" title="&quot;IPv6 over ATM Networks&quot;">RFC2492</a>]

   -  Transmission of IPv6 Packets over Frame Relay Networks
      Specification [<a href="./rfc2590" title="&quot;Transmission of IPv6 Packets over Frame Relay Networks Specification&quot;">RFC2590</a>]

   -  Transmission of IPv6 Packets over IEEE 1394 Networks [<a href="./rfc3146" title="&quot;Transmission of IPv6 Packets over IEEE 1394 Networks&quot;">RFC3146</a>]

   -  Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP)
      Packets over Fibre Channel [<a href="./rfc4338" title="&quot;Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) Packets over Fibre Channel&quot;">RFC4338</a>]

   -  Transmission of IPv6 Packets over IEEE 802.15.4 Networks [<a href="./rfc4944" title="&quot;Transmission of IPv6 Packets over IEEE 802.15.4 Networks&quot;">RFC4944</a>]

   -  Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE
      802.16 Networks [<a href="./rfc5121" title="&quot;Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE 802.16 Networks&quot;">RFC5121</a>]

   -  IP version 6 over PPP [<a href="./rfc5072" title="&quot;IP Version 6 over PPP&quot;">RFC5072</a>]






<span class="grey">Jankiewicz, et al.            Informational                     [Page 6]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-7" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   In addition to traditional physical link-layers, it is also possible
   to tunnel IPv6 over other protocols.  Examples include:

   -  Teredo: Tunneling IPv6 over UDP through Network Address
      Translations (NATs) [<a href="./rfc4380" title="&quot;Teredo: Tunneling IPv6 over UDP through Network Address Translations (NATs)&quot;">RFC4380</a>]

   -  <a href="#section-3">Section 3</a> of "Basic Transition Mechanisms for IPv6 Hosts and
      Routers" [<a href="./rfc4213" title="&quot;Basic Transition Mechanisms for IPv6 Hosts and Routers&quot;">RFC4213</a>]

<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>.  IP Layer</span>

<span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>.  Internet Protocol Version 6 - <a href="./rfc2460">RFC 2460</a></span>

   The Internet Protocol Version 6 is specified in [<a href="./rfc2460" title="&quot;Internet Protocol, Version 6 (IPv6) Specification&quot;">RFC2460</a>].  This
   specification MUST be supported.

   Any unrecognized extension headers or options MUST be processed as
   described in <a href="./rfc2460">RFC 2460</a>.

   The node MUST follow the packet transmission rules in <a href="./rfc2460">RFC 2460</a>.

   Nodes MUST always be able to send, receive, and process fragment
   headers.  All conformant IPv6 implementations MUST be capable of
   sending and receiving IPv6 packets; the forwarding functionality MAY
   be supported.  Overlapping fragments MUST be handled as described in
   [<a href="./rfc5722" title="&quot;Handling of Overlapping IPv6 Fragments&quot;">RFC5722</a>].

   <a href="./rfc2460">RFC 2460</a> specifies extension headers and the processing for these
   headers.

   An IPv6 node MUST be able to process these headers.  An exception is
   Routing Header type 0 (RH0), which was deprecated by [<a href="./rfc5095" title="&quot;Deprecation of Type 0 Routing Headers in IPv6&quot;">RFC5095</a>] due to
   security concerns and which MUST be treated as an unrecognized
   routing type.

   All nodes SHOULD support the setting and use of the IPv6 Flow Label
   field as defined in the IPv6 Flow Label specification [<a href="./rfc6437" title="&quot;IPv6 Flow Label Specification&quot;">RFC6437</a>].
   Forwarding nodes such as routers and load distributors MUST NOT
   depend only on Flow Label values being uniformly distributed.  It is
   RECOMMENDED that source hosts support the flow label by setting the
   Flow Label field for all packets of a given flow to the same value
   chosen from an approximation to a discrete uniform distribution.









<span class="grey">Jankiewicz, et al.            Informational                     [Page 7]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-8" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h3"><a class="selflink" id="section-5.2" href="#section-5.2">5.2</a>.  Neighbor Discovery for IPv6 - <a href="./rfc4861">RFC 4861</a></span>

   Neighbor Discovery is defined in [<a href="./rfc4861" title="&quot;Neighbor Discovery for IP version 6 (IPv6)&quot;">RFC4861</a>]; the definition was
   updated by [<a href="./rfc5942" title="&quot;IPv6 Subnet Model: The Relationship between Links and Subnet Prefixes&quot;">RFC5942</a>].  Neighbor Discovery SHOULD be supported.  <a href="./rfc4861">RFC</a>
   <a href="./rfc4861">4861</a> states:

      Unless specified otherwise (in a document that covers operating IP
      over a particular link type) this document applies to all link
      types.  However, because ND uses link-layer multicast for some of
      its services, it is possible that on some link types (e.g., Non-
      Broadcast Multi-Access (NBMA) links), alternative protocols or
      mechanisms to implement those services will be specified (in the
      appropriate document covering the operation of IP over a
      particular link type).  The services described in this document
      that are not directly dependent on multicast, such as Redirects,
      next-hop determination, Neighbor Unreachability Detection, etc.,
      are expected to be provided as specified in this document.  The
      details of how one uses ND on NBMA links are addressed in
      [<a href="./rfc2491" title="&quot;IPv6 over Non-Broadcast Multiple Access (NBMA) networks&quot;">RFC2491</a>].

   Some detailed analysis of Neighbor Discovery follows:

   Router Discovery is how hosts locate routers that reside on an
   attached link.  Hosts MUST support Router Discovery functionality.

   Prefix Discovery is how hosts discover the set of address prefixes
   that define which destinations are on-link for an attached link.
   Hosts MUST support Prefix Discovery.

   Hosts MUST also implement Neighbor Unreachability Detection (NUD) for
   all paths between hosts and neighboring nodes.  NUD is not required
   for paths between routers.  However, all nodes MUST respond to
   unicast Neighbor Solicitation (NS) messages.

   Hosts MUST support the sending of Router Solicitations and the
   receiving of Router Advertisements.  The ability to understand
   individual Router Advertisement options is dependent on supporting
   the functionality making use of the particular option.

   All nodes MUST support the sending and receiving of Neighbor
   Solicitation (NS) and Neighbor Advertisement (NA) messages.  NS and
   NA messages are required for Duplicate Address Detection (DAD).

   Hosts SHOULD support the processing of Redirect functionality.
   Routers MUST support the sending of Redirects, though not necessarily
   for every individual packet (e.g., due to rate limiting).  Redirects
   are only useful on networks supporting hosts.  In core networks
   dominated by routers, Redirects are typically disabled.  The sending



<span class="grey">Jankiewicz, et al.            Informational                     [Page 8]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-9" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   of Redirects SHOULD be disabled by default on backbone routers.  They
   MAY be enabled by default on routers intended to support hosts on
   edge networks.

   "IPv6 Host-to-Router Load Sharing" [<a href="./rfc4311" title="&quot;IPv6 Host-to-Router Load Sharing&quot;">RFC4311</a>] includes additional
   recommendations on how to select from a set of available routers.
   [<a href="./rfc4311" title="&quot;IPv6 Host-to-Router Load Sharing&quot;">RFC4311</a>] SHOULD be supported.

<span class="h3"><a class="selflink" id="section-5.3" href="#section-5.3">5.3</a>.  Default Router Preferences and More-Specific Routes - <a href="./rfc4191">RFC 4191</a></span>

   "Default Router Preferences and More-Specific Routes" [<a href="./rfc4191" title="&quot;Default Router Preferences and More-Specific Routes&quot;">RFC4191</a>]
   provides support for nodes attached to multiple (different) networks,
   each providing routers that advertise themselves as default routers
   via Router Advertisements.  In some scenarios, one router may provide
   connectivity to destinations the other router does not, and choosing
   the "wrong" default router can result in reachability failures.  In
   such cases, <a href="./rfc4191">RFC 4191</a> can help.

   Small Office/Home Office (SOHO) deployments supported by routers
   adhering to [<a href="./rfc6204" title="&quot;Basic Requirements for IPv6 Customer Edge Routers&quot;">RFC6204</a>] use <a href="./rfc4191">RFC 4191</a> to advertise routes to certain
   local destinations.  Consequently, nodes that will be deployed in
   SOHO environments SHOULD implement <a href="./rfc4191">RFC 4191</a>.

<span class="h3"><a class="selflink" id="section-5.4" href="#section-5.4">5.4</a>.  SEcure Neighbor Discovery (SEND) - <a href="./rfc3971">RFC 3971</a></span>

   SEND [<a href="./rfc3971" title="&quot;SEcure Neighbor Discovery (SEND)&quot;">RFC3971</a>] and Cryptographically Generated Address (CGA)
   [<a href="./rfc3972" title="&quot;Cryptographically Generated Addresses (CGA)&quot;">RFC3972</a>] provide a way to secure the message exchanges of Neighbor
   Discovery.  SEND is a new technology in that it has no IPv4
   counterpart, but it has significant potential to address certain
   classes of spoofing attacks.  While there have been some
   implementations of SEND, there has been only limited deployment
   experience to date in using the technology.  In addition, the IETF
   working group Cga &amp; Send maIntenance (csi) is currently working on
   additional extensions intended to make SEND more attractive for
   deployment.

   At this time, SEND is considered optional, and IPv6 nodes MAY provide
   SEND functionality.

<span class="h3"><a class="selflink" id="section-5.5" href="#section-5.5">5.5</a>.  IPv6 Router Advertisement Flags Option - <a href="./rfc5175">RFC 5175</a></span>

   Router Advertisements include an 8-bit field of single-bit Router
   Advertisement flags.  The Router Advertisement Flags Option extends
   the number of available flag bits by 48 bits.  At the time of this
   writing, 6 of the original 8 single-bit flags have been assigned,
   while 2 remain available for future assignment.  No flags have been
   defined that make use of the new option, and thus, strictly speaking,
   there is no requirement to implement the option today.  However,



<span class="grey">Jankiewicz, et al.            Informational                     [Page 9]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-10" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   implementations that are able to pass unrecognized options to a
   higher-level entity that may be able to understand them (e.g., a
   user-level process using a "raw socket" facility) MAY take steps to
   handle the option in anticipation of a future usage.

<span class="h3"><a class="selflink" id="section-5.6" href="#section-5.6">5.6</a>.  Path MTU Discovery and Packet Size</span>

<span class="h4"><a class="selflink" id="section-5.6.1" href="#section-5.6.1">5.6.1</a>.  Path MTU Discovery - <a href="./rfc1981">RFC 1981</a></span>

   "Path MTU Discovery for IP version 6" [<a href="./rfc1981" title="&quot;Path MTU Discovery for IP version 6&quot;">RFC1981</a>] SHOULD be supported.
   From [<a href="./rfc2460" title="&quot;Internet Protocol, Version 6 (IPv6) Specification&quot;">RFC2460</a>]:

      It is strongly recommended that IPv6 nodes implement Path MTU
      Discovery [<a href="./rfc1981" title="&quot;Path MTU Discovery for IP version 6&quot;">RFC1981</a>], in order to discover and take advantage of
      path MTUs greater than 1280 octets.  However, a minimal IPv6
      implementation (e.g., in a boot ROM) may simply restrict itself to
      sending packets no larger than 1280 octets, and omit
      implementation of Path MTU Discovery.

   The rules in [<a href="./rfc2460" title="&quot;Internet Protocol, Version 6 (IPv6) Specification&quot;">RFC2460</a>] and [<a href="./rfc5722" title="&quot;Handling of Overlapping IPv6 Fragments&quot;">RFC5722</a>] MUST be followed for packet
   fragmentation and reassembly.

   One operational issue with Path MTU Discovery occurs when firewalls
   block ICMP Packet Too Big messages.  Path MTU Discovery relies on
   such messages to determine what size messages can be successfully
   sent.  "Packetization Layer Path MTU Discovery" [<a href="./rfc4821" title="&quot;Packetization Layer Path MTU Discovery&quot;">RFC4821</a>] avoids
   having a dependency on Packet Too Big messages.

<span class="h3"><a class="selflink" id="section-5.7" href="#section-5.7">5.7</a>.  IPv6 Jumbograms - <a href="./rfc2675">RFC 2675</a></span>

   IPv6 Jumbograms [<a href="./rfc2675" title="&quot;IPv6 Jumbograms&quot;">RFC2675</a>] are an optional extension that allow the
   sending of IP datagrams larger than 65.535 bytes.  IPv6 Jumbograms
   make use of IPv6 hop-by-hop options and are only suitable on paths in
   which every hop and link are capable of supporting Jumbograms (e.g.,
   within a campus or datacenter).  To date, few implementations exist,
   and there is essentially no reported experience from usage.

   Consequently, IPv6 Jumbograms [<a href="./rfc2675" title="&quot;IPv6 Jumbograms&quot;">RFC2675</a>] remain optional at this time.

<span class="h3"><a class="selflink" id="section-5.8" href="#section-5.8">5.8</a>.  ICMP for the Internet Protocol Version 6 (IPv6) - <a href="./rfc4443">RFC 4443</a></span>

   ICMPv6 [<a href="./rfc4443" title="&quot;Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification&quot;">RFC4443</a>] MUST be supported.  "Extended ICMP to Support Multi-
   Part Messages" [<a href="./rfc4884" title="&quot;Extended ICMP to Support Multi-Part Messages&quot;">RFC4884</a>] MAY be supported.








<span class="grey">Jankiewicz, et al.            Informational                    [Page 10]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-11" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h3"><a class="selflink" id="section-5.9" href="#section-5.9">5.9</a>.  Addressing</span>

<span class="h4"><a class="selflink" id="section-5.9.1" href="#section-5.9.1">5.9.1</a>.  IP Version 6 Addressing Architecture - <a href="./rfc4291">RFC 4291</a></span>

   The IPv6 Addressing Architecture [<a href="./rfc4291" title="&quot;IP Version 6 Addressing Architecture&quot;">RFC4291</a>] MUST be supported.

<span class="h4"><a class="selflink" id="section-5.9.2" href="#section-5.9.2">5.9.2</a>.  IPv6 Stateless Address Autoconfiguration - <a href="./rfc4862">RFC 4862</a></span>

   Hosts MUST support IPv6 Stateless Address Autoconfiguration as
   defined in [<a href="./rfc4862" title="&quot;IPv6 Stateless Address Autoconfiguration&quot;">RFC4862</a>].  Configuration of static address(es) may be
   supported as well.

   Nodes that are routers MUST be able to generate link-local addresses
   as described in [<a href="./rfc4862" title="&quot;IPv6 Stateless Address Autoconfiguration&quot;">RFC4862</a>].

   From <a href="./rfc4862">RFC 4862</a>:

      The autoconfiguration process specified in this document applies
      only to hosts and not routers.  Since host autoconfiguration uses
      information advertised by routers, routers will need to be
      configured by some other means.  However, it is expected that
      routers will generate link-local addresses using the mechanism
      described in this document.  In addition, routers are expected to
      successfully pass the Duplicate Address Detection procedure
      described in this document on all addresses prior to assigning
      them to an interface.

   All nodes MUST implement Duplicate Address Detection.  Quoting from
   <a href="./rfc4862#section-5.4">Section&nbsp;5.4 of RFC 4862</a>:

      Duplicate Address Detection MUST be performed on all unicast
      addresses prior to assigning them to an interface, regardless of
      whether they are obtained through stateless autoconfiguration,
      DHCPv6, or manual configuration, with the following [exceptions
      noted therein].

   "Optimistic Duplicate Address Detection (DAD) for IPv6" [<a href="./rfc4429" title="&quot;Optimistic Duplicate Address Detection (DAD) for IPv6&quot;">RFC4429</a>]
   specifies a mechanism to reduce delays associated with generating
   addresses via Stateless Address Autoconfiguration [<a href="./rfc4862" title="&quot;IPv6 Stateless Address Autoconfiguration&quot;">RFC4862</a>].  <a href="./rfc4429">RFC</a>
   <a href="./rfc4429">4429</a> was developed in conjunction with Mobile IPv6 in order to reduce
   the time needed to acquire and configure addresses as devices quickly
   move from one network to another, and it is desirable to minimize
   transition delays.  For general purpose devices, <a href="./rfc4429">RFC 4429</a> remains
   optional at this time.







<span class="grey">Jankiewicz, et al.            Informational                    [Page 11]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-12" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h4"><a class="selflink" id="section-5.9.3" href="#section-5.9.3">5.9.3</a>.  Privacy Extensions for Address Configuration in IPv6 - <a href="./rfc4941">RFC 4941</a></span>

   Privacy Extensions for Stateless Address Autoconfiguration [<a href="./rfc4941" title="&quot;Privacy Extensions for Stateless Address Autoconfiguration in IPv6&quot;">RFC4941</a>]
   addresses a specific problem involving a client device whose user is
   concerned about its activity or location being tracked.  The problem
   arises both for a static client and for one that regularly changes
   its point of attachment to the Internet.  When using Stateless
   Address Autoconfiguration [<a href="./rfc4862" title="&quot;IPv6 Stateless Address Autoconfiguration&quot;">RFC4862</a>], the Interface Identifier portion
   of formed addresses stays constant and is globally unique.  Thus,
   although a node's global IPv6 address will change if it changes its
   point of attachment, the Interface Identifier portion of those
   addresses remains the same, making it possible for servers to track
   the location of an individual device as it moves around or its
   pattern of activity if it remains in one place.  This may raise
   privacy concerns as described in [<a href="./rfc4862" title="&quot;IPv6 Stateless Address Autoconfiguration&quot;">RFC4862</a>].

   In such situations, <a href="./rfc4941">RFC 4941</a> SHOULD be implemented.  In other cases,
   such as with dedicated servers in a data center, <a href="./rfc4941">RFC 4941</a> provides
   limited or no benefit.

   Implementers of <a href="./rfc4941">RFC 4941</a> should be aware that certain addresses are
   reserved and should not be chosen for use as temporary addresses.
   Consult "Reserved IPv6 Interface Identifiers" [<a href="./rfc5453" title="&quot;Reserved IPv6 Interface Identifiers&quot;">RFC5453</a>] for more
   details.

<span class="h4"><a class="selflink" id="section-5.9.4" href="#section-5.9.4">5.9.4</a>.  Default Address Selection for IPv6 - <a href="./rfc3484">RFC 3484</a></span>

   The rules specified in the Default Address Selection for IPv6
   [<a href="./rfc3484" title="&quot;Default Address Selection for Internet Protocol version 6 (IPv6)&quot;">RFC3484</a>] document MUST be implemented.  IPv6 nodes will need to deal
   with multiple addresses configured simultaneously.

<span class="h4"><a class="selflink" id="section-5.9.5" href="#section-5.9.5">5.9.5</a>.  Stateful Address Autoconfiguration (DHCPv6) - <a href="./rfc3315">RFC 3315</a></span>

   DHCPv6 [<a href="./rfc3315" title="&quot;Dynamic Host Configuration Protocol for IPv6 (DHCPv6)&quot;">RFC3315</a>] can be used to obtain and configure addresses.  In
   general, a network may provide for the configuration of addresses
   through Router Advertisements, DHCPv6, or both.  There will be a wide
   range of IPv6 deployment models and differences in address assignment
   requirements, some of which may require DHCPv6 for address
   assignment.  Consequently, all hosts SHOULD implement address
   configuration via DHCPv6.

   In the absence of a router, IPv6 nodes using DHCP for address
   assignment MAY initiate DHCP to obtain IPv6 addresses and other
   configuration information, as described in <a href="./rfc4862#section-5.5.2">Section&nbsp;5.5.2 of
   [RFC4862]</a>.






<span class="grey">Jankiewicz, et al.            Informational                    [Page 12]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-13" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h3"><a class="selflink" id="section-5.10" href="#section-5.10">5.10</a>.  Multicast Listener Discovery (MLD) for IPv6</span>

   Nodes that need to join multicast groups MUST support MLDv1
   [<a href="./rfc2710" title="&quot;Multicast Listener Discovery (MLD) for IPv6&quot;">RFC2710</a>].  MLDv1 is needed by any node that is expected to receive
   and process multicast traffic.  Note that Neighbor Discovery (as used
   on most link types -- see <a href="#section-5.2">Section 5.2</a>) depends on multicast and
   requires that nodes join Solicited Node multicast addresses.

   MLDv2 [<a href="./rfc3810" title="&quot;Multicast Listener Discovery Version 2 (MLDv2) for IPv6&quot;">RFC3810</a>] extends the functionality of MLDv1 by supporting
   Source-Specific Multicast.  The original MLDv2 protocol [<a href="./rfc3810" title="&quot;Multicast Listener Discovery Version 2 (MLDv2) for IPv6&quot;">RFC3810</a>]
   supporting Source-Specific Multicast [<a href="./rfc4607" title="&quot;Source-Specific Multicast for IP&quot;">RFC4607</a>] supports two types of
   "filter modes".  Using an INCLUDE filter, a node indicates a
   multicast group along with a list of senders for the group from which
   it wishes to receive traffic.  Using an EXCLUDE filter, a node
   indicates a multicast group along with a list of senders from which
   it wishes to exclude receiving traffic.  In practice, operations to
   block source(s) using EXCLUDE mode are rarely used but add
   considerable implementation complexity to MLDv2.  Lightweight MLDv2
   [<a href="./rfc5790" title="&quot;Lightweight Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols&quot;">RFC5790</a>] is a simplified subset of the original MLDv2 specification
   that omits EXCLUDE filter mode to specify undesired source(s).

   Nodes SHOULD implement either MLDv2 [<a href="./rfc3810" title="&quot;Multicast Listener Discovery Version 2 (MLDv2) for IPv6&quot;">RFC3810</a>] or Lightweight MLDv2
   [<a href="./rfc5790" title="&quot;Lightweight Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols&quot;">RFC5790</a>].  Specifically, nodes supporting applications using Source-
   Specific Multicast that expect to take advantage of MLDv2's EXCLUDE
   functionality [<a href="./rfc3810" title="&quot;Multicast Listener Discovery Version 2 (MLDv2) for IPv6&quot;">RFC3810</a>] MUST support MLDv2 as defined in [<a href="./rfc3810" title="&quot;Multicast Listener Discovery Version 2 (MLDv2) for IPv6&quot;">RFC3810</a>],
   [<a href="./rfc4604" title="&quot;Using Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Protocol Version 2 (MLDv2) for Source- Specific Multicast&quot;">RFC4604</a>], and [<a href="./rfc4607" title="&quot;Source-Specific Multicast for IP&quot;">RFC4607</a>].  Nodes supporting applications that expect
   to only take advantage of MLDv2's INCLUDE functionality as well as
   Any-Source Multicast will find it sufficient to support MLDv2 as
   defined in [<a href="./rfc5790" title="&quot;Lightweight Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols&quot;">RFC5790</a>].

   If a node only supports applications that use Any-Source Multicast
   (i.e, they do not use Source-Specific Multicast), implementing MLDv1
   [<a href="./rfc2710" title="&quot;Multicast Listener Discovery (MLD) for IPv6&quot;">RFC2710</a>] is sufficient.  In all cases, however, nodes are strongly
   encouraged to implement MLDv2 or Lightweight MLDv2 rather than MLDv1,
   as the presence of a single MLDv1 participant on a link requires that
   all other nodes on the link operate in version 1 compatibility mode.

   When MLDv1 is used, the rules in the Source Address Selection for the
   Multicast Listener Discovery (MLD) Protocol [<a href="./rfc3590" title="&quot;Source Address Selection for the Multicast Listener Discovery (MLD) Protocol&quot;">RFC3590</a>] MUST be
   followed.

<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>.  DHCP versus Router Advertisement Options for Host Configuration</span>

   In IPv6, there are two main protocol mechanisms for propagating
   configuration information to hosts: Router Advertisements (RAs) and
   DHCP.  Historically, RA options have been restricted to those deemed
   essential for basic network functioning and for which all nodes are
   configured with exactly the same information.  Examples include the



<span class="grey">Jankiewicz, et al.            Informational                    [Page 13]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-14" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   Prefix Information Options, the MTU option, etc.  On the other hand,
   DHCP has generally been preferred for configuration of more general
   parameters and for parameters that may be client-specific.  That
   said, identifying the exact line on whether a particular option
   should be configured via DHCP versus an RA option has not always been
   easy.  Generally speaking, however, there has been a desire to define
   only one mechanism for configuring a given option, rather than
   defining multiple (different) ways of configuring the same
   information.

   One issue with having multiple ways of configuring the same
   information is that interoperability suffers if a host chooses one
   mechanism but the network operator chooses a different mechanism.
   For "closed" environments, where the network operator has significant
   influence over what devices connect to the network and thus what
   configuration mechanisms they support, the operator may be able to
   ensure that a particular mechanism is supported by all connected
   hosts.  In more open environments, however, where arbitrary devices
   may connect (e.g., a WIFI hotspot), problems can arise.  To maximize
   interoperability in such environments, hosts would need to implement
   multiple configuration mechanisms to ensure interoperability.

   Originally, in IPv6, configuring information about DNS servers was
   performed exclusively via DHCP.  In 2007, an RA option was defined
   but was published as Experimental [<a href="./rfc5006" title="&quot;IPv6 Router Advertisement Option for DNS Configuration&quot;">RFC5006</a>].  In 2010, "IPv6 Router
   Advertisement Options for DNS Configuration" [<a href="./rfc6106" title="&quot;IPv6 Router Advertisement Options for DNS Configuration&quot;">RFC6106</a>] was published
   as a Standards Track document.  Consequently, DNS configuration
   information can now be learned either through DHCP or through RAs.
   Hosts will need to decide which mechanism (or whether both) should be
   implemented.  Specific guidance regarding DNS server discovery is
   discussed in <a href="#section-7">Section 7</a>.

<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>.  DNS and DHCP</span>

<span class="h3"><a class="selflink" id="section-7.1" href="#section-7.1">7.1</a>.  DNS</span>

   DNS is described in [<a href="./rfc1034" title="&quot;Domain names - concepts and facilities&quot;">RFC1034</a>], [<a href="./rfc1035" title="&quot;Domain names - implementation and specification&quot;">RFC1035</a>], [<a href="./rfc3363" title="&quot;Representing Internet Protocol version 6 (IPv6) Addresses in the Domain Name System (DNS)&quot;">RFC3363</a>], and [<a href="./rfc3596" title="&quot;DNS Extensions to Support IP Version 6&quot;">RFC3596</a>].
   Not all nodes will need to resolve names; those that will never need
   to resolve DNS names do not need to implement resolver functionality.
   However, the ability to resolve names is a basic infrastructure
   capability on which applications rely, and most nodes will need to
   provide support.  All nodes SHOULD implement stub-resolver [<a href="./rfc1034" title="&quot;Domain names - concepts and facilities&quot;">RFC1034</a>]
   functionality, as in <a href="./rfc1034#section-5.3.1">[RFC1034], Section&nbsp;5.3.1</a>, with support for:

   -  AAAA type Resource Records [<a href="./rfc3596" title="&quot;DNS Extensions to Support IP Version 6&quot;">RFC3596</a>];

   -  reverse addressing in ip6.arpa using PTR records [<a href="./rfc3596" title="&quot;DNS Extensions to Support IP Version 6&quot;">RFC3596</a>];




<span class="grey">Jankiewicz, et al.            Informational                    [Page 14]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-15" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   -  Extension Mechanisms for DNS (EDNS0) [<a href="./rfc2671" title="&quot;Extension Mechanisms for DNS (EDNS0)&quot;">RFC2671</a>] to allow for DNS
      packet sizes larger than 512 octets.

   Those nodes are RECOMMENDED to support DNS security extensions
   [<a href="./rfc4033" title="&quot;DNS Security Introduction and Requirements&quot;">RFC4033</a>] [<a href="./rfc4034" title="&quot;Resource Records for the DNS Security Extensions&quot;">RFC4034</a>] [<a href="./rfc4035" title="&quot;Protocol Modifications for the DNS Security Extensions&quot;">RFC4035</a>].

   Those nodes are NOT RECOMMENDED to support the experimental A6
   Resource Records [<a href="./rfc3363" title="&quot;Representing Internet Protocol version 6 (IPv6) Addresses in the Domain Name System (DNS)&quot;">RFC3363</a>].

<span class="h3"><a class="selflink" id="section-7.2" href="#section-7.2">7.2</a>.  Dynamic Host Configuration Protocol for IPv6 (DHCPv6) - <a href="./rfc3315">RFC 3315</a></span>

<span class="h4"><a class="selflink" id="section-7.2.1" href="#section-7.2.1">7.2.1</a>.  Other Configuration Information</span>

   IPv6 nodes use DHCP [<a href="./rfc3315" title="&quot;Dynamic Host Configuration Protocol for IPv6 (DHCPv6)&quot;">RFC3315</a>] to obtain address configuration
   information (see <a href="#section-5.9.5">Section 5.9.5</a>) and to obtain additional (non-
   address) configuration.  If a host implementation supports
   applications or other protocols that require configuration that is
   only available via DHCP, hosts SHOULD implement DHCP.  For
   specialized devices on which no such configuration need is present,
   DHCP may not be necessary.

   An IPv6 node can use the subset of DHCP (described in [<a href="./rfc3736" title="&quot;Stateless Dynamic Host Configuration Protocol (DHCP) Service for IPv6&quot;">RFC3736</a>]) to
   obtain other configuration information.

<span class="h4"><a class="selflink" id="section-7.2.2" href="#section-7.2.2">7.2.2</a>.  Use of Router Advertisements in Managed Environments</span>

   Nodes using the Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
   are expected to determine their default router information and on-
   link prefix information from received Router Advertisements.

<span class="h3"><a class="selflink" id="section-7.3" href="#section-7.3">7.3</a>.  IPv6 Router Advertisement Options for DNS Configuration - <a href="./rfc6106">RFC 6106</a></span>

   Router Advertisements have historically limited options to those that
   are critical to basic IPv6 functioning.  Originally, DNS
   configuration was not included as an RA option, and DHCP was the
   recommended way to obtain DNS configuration information.  Over time,
   the thinking surrounding such an option has evolved.  It is now
   generally recognized that few nodes can function adequately without
   having access to a working DNS resolver.  [<a href="./rfc5006" title="&quot;IPv6 Router Advertisement Option for DNS Configuration&quot;">RFC5006</a>] was published as
   an Experimental document in 2007, and recently, a revised version was
   placed on the Standards Track [<a href="./rfc6106" title="&quot;IPv6 Router Advertisement Options for DNS Configuration&quot;">RFC6106</a>].

   Implementations SHOULD implement the DNS RA option [<a href="./rfc6106" title="&quot;IPv6 Router Advertisement Options for DNS Configuration&quot;">RFC6106</a>].








<span class="grey">Jankiewicz, et al.            Informational                    [Page 15]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-16" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>.  IPv4 Support and Transition</span>

   IPv6 nodes MAY support IPv4.

<span class="h3"><a class="selflink" id="section-8.1" href="#section-8.1">8.1</a>.  Transition Mechanisms</span>

<span class="h4"><a class="selflink" id="section-8.1.1" href="#section-8.1.1">8.1.1</a>.  Basic Transition Mechanisms for IPv6 Hosts and Routers - <a href="./rfc4213">RFC</a></span>
        <a href="./rfc4213">4213</a>

   If an IPv6 node implements dual stack and tunneling, then [<a href="./rfc4213" title="&quot;Basic Transition Mechanisms for IPv6 Hosts and Routers&quot;">RFC4213</a>]
   MUST be supported.

<span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>.  Application Support</span>

<span class="h3"><a class="selflink" id="section-9.1" href="#section-9.1">9.1</a>.  Textual Representation of IPv6 Addresses - <a href="./rfc5952">RFC 5952</a></span>

   Software that allows users and operators to input IPv6 addresses in
   text form SHOULD support "A Recommendation for IPv6 Address Text
   Representation" [<a href="./rfc5952" title="&quot;A Recommendation for IPv6 Address Text Representation&quot;">RFC5952</a>].

<span class="h3"><a class="selflink" id="section-9.2" href="#section-9.2">9.2</a>.  Application Programming Interfaces (APIs)</span>

   There are a number of IPv6-related APIs.  This document does not
   mandate the use of any, because the choice of API does not directly
   relate to on-the-wire behavior of protocols.  Implementers, however,
   would be advised to consider providing a common API or reviewing
   existing APIs for the type of functionality they provide to
   applications.

   "Basic Socket Interface Extensions for IPv6" [<a href="./rfc3493" title="&quot;Basic Socket Interface Extensions for IPv6&quot;">RFC3493</a>] provides IPv6
   functionality used by typical applications.  Implementers should note
   that <a href="./rfc3493">RFC3493</a> has been picked up and further standardized by the
   Portable Operating System Interface (POSIX) [<a href="#ref-POSIX" title="&quot;IEEE Std. 1003.1-2008 Standard for Information Technology -- Portable Operating System Interface (POSIX), ISO/IEC 9945:2009&quot;">POSIX</a>].

   "Advanced Sockets Application Program Interface (API) for IPv6"
   [<a href="./rfc3542" title="&quot;Advanced Sockets Application Program Interface (API) for IPv6&quot;">RFC3542</a>] provides access to advanced IPv6 features needed by
   diagnostic and other more specialized applications.

   "IPv6 Socket API for Source Address Selection" [<a href="./rfc5014" title="&quot;IPv6 Socket API for Source Address Selection&quot;">RFC5014</a>] provides
   facilities that allow an application to override the default Source
   Address Selection rules of [<a href="./rfc3484" title="&quot;Default Address Selection for Internet Protocol version 6 (IPv6)&quot;">RFC3484</a>].

   "Socket Interface Extensions for Multicast Source Filters" [<a href="./rfc3678" title="&quot;Socket Interface Extensions for Multicast Source Filters&quot;">RFC3678</a>]
   provides support for expressing source filters on multicast group
   memberships.






<span class="grey">Jankiewicz, et al.            Informational                    [Page 16]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-17" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   "Extension to Sockets API for Mobile IPv6" [<a href="./rfc4584" title="&quot;Extension to Sockets API for Mobile IPv6&quot;">RFC4584</a>] provides
   application support for accessing and enabling Mobile IPv6 [<a href="./rfc6275" title="&quot;Mobility Support in IPv6&quot;">RFC6275</a>]
   features.

<span class="h2"><a class="selflink" id="section-10" href="#section-10">10</a>.  Mobility</span>

   Mobile IPv6 [<a href="./rfc6275" title="&quot;Mobility Support in IPv6&quot;">RFC6275</a>] and associated specifications [<a href="./rfc3776" title="&quot;Using IPsec to Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents&quot;">RFC3776</a>]
   [<a href="./rfc4877" title="&quot;Mobile IPv6 Operation with IKEv2 and the Revised IPsec Architecture&quot;">RFC4877</a>] allow a node to change its point of attachment within the
   Internet, while maintaining (and using) a permanent address.  All
   communication using the permanent address continues to proceed as
   expected even as the node moves around.  The definition of Mobile IP
   includes requirements for the following types of nodes:

      - mobile nodes

      - correspondent nodes with support for route optimization

      - home agents

      - all IPv6 routers

   At the present time, Mobile IP has seen only limited implementation
   and no significant deployment, partly because it originally assumed
   an IPv6-only environment rather than a mixed IPv4/IPv6 Internet.
   Recently, additional work has been done to support mobility in mixed-
   mode IPv4 and IPv6 networks [<a href="./rfc5555" title="&quot;Mobile IPv6 Support for Dual Stack Hosts and Routers&quot;">RFC5555</a>].

   More usage and deployment experience is needed with mobility before
   any specific approach can be recommended for broad implementation in
   all hosts and routers.  Consequently, [<a href="./rfc6275" title="&quot;Mobility Support in IPv6&quot;">RFC6275</a>], [<a href="./rfc5555" title="&quot;Mobile IPv6 Support for Dual Stack Hosts and Routers&quot;">RFC5555</a>], and
   associated standards such as [<a href="./rfc4877" title="&quot;Mobile IPv6 Operation with IKEv2 and the Revised IPsec Architecture&quot;">RFC4877</a>] are considered a MAY at this
   time.

<span class="h2"><a class="selflink" id="section-11" href="#section-11">11</a>.  Security</span>

   This section describes the specification for security for IPv6 nodes.

   Achieving security in practice is a complex undertaking.  Operational
   procedures, protocols, key distribution mechanisms, certificate
   management approaches, etc., are all components that impact the level
   of security actually achieved in practice.  More importantly,
   deficiencies or a poor fit in any one individual component can
   significantly reduce the overall effectiveness of a particular
   security approach.







<span class="grey">Jankiewicz, et al.            Informational                    [Page 17]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-18" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   IPsec provides channel security at the Internet layer, making it
   possible to provide secure communication for all (or a subset of)
   communication flows at the IP layer between pairs of internet nodes.
   IPsec provides sufficient flexibility and granularity that individual
   TCP connections can (selectively) be protected, etc.

   Although IPsec can be used with manual keying in some cases, such
   usage has limited applicability and is not recommended.

   A range of security technologies and approaches proliferate today
   (e.g., IPsec, Transport Layer Security (TLS), Secure SHell (SSH),
   etc.)  No one approach has emerged as an ideal technology for all
   needs and environments.  Moreover, IPsec is not viewed as the ideal
   security technology in all cases and is unlikely to displace the
   others.

   Previously, IPv6 mandated implementation of IPsec and recommended the
   key management approach of IKE.  This document updates that
   recommendation by making support of the IPsec Architecture [<a href="./rfc4301" title="&quot;Security Architecture for the Internet Protocol&quot;">RFC4301</a>]
   a SHOULD for all IPv6 nodes.  Note that the IPsec Architecture
   requires (e.g., <a href="./rfc4301#section-4.5">Section&nbsp;4.5 of RFC 4301</a>) the implementation of both
   manual and automatic key management.  Currently, the default
   automated key management protocol to implement is IKEv2 [<a href="./rfc5996" title="&quot;Internet Key Exchange Protocol Version 2 (IKEv2)&quot;">RFC5996</a>].

   This document recognizes that there exists a range of device types
   and environments where approaches to security other than IPsec can be
   justified.  For example, special-purpose devices may support only a
   very limited number or type of applications, and an application-
   specific security approach may be sufficient for limited management
   or configuration capabilities.  Alternatively, some devices may run
   on extremely constrained hardware (e.g., sensors) where the full
   IPsec Architecture is not justified.

<span class="h3"><a class="selflink" id="section-11.1" href="#section-11.1">11.1</a>.  Requirements</span>

   "Security Architecture for the Internet Protocol" [<a href="./rfc4301" title="&quot;Security Architecture for the Internet Protocol&quot;">RFC4301</a>] SHOULD be
   supported by all IPv6 nodes.  Note that the IPsec Architecture
   requires (e.g., <a href="./rfc4301#section-4.5">Section&nbsp;4.5 of [RFC4301]</a>) the implementation of both
   manual and automatic key management.  Currently, the default
   automated key management protocol to implement is IKEv2.  As required
   in [<a href="./rfc4301" title="&quot;Security Architecture for the Internet Protocol&quot;">RFC4301</a>], IPv6 nodes implementing the IPsec Architecture MUST
   implement ESP [<a href="./rfc4303" title="&quot;IP Encapsulating Security Payload (ESP)&quot;">RFC4303</a>] and MAY implement AH [<a href="./rfc4302" title="&quot;IP Authentication Header&quot;">RFC4302</a>].









<span class="grey">Jankiewicz, et al.            Informational                    [Page 18]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-19" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h3"><a class="selflink" id="section-11.2" href="#section-11.2">11.2</a>.  Transforms and Algorithms</span>

   The current set of mandatory-to-implement algorithms for the IPsec
   Architecture are defined in "Cryptographic Algorithm Implementation
   Requirements For ESP and AH" [<a href="./rfc4835" title="&quot;Cryptographic Algorithm Implementation Requirements for Encapsulating Security Payload (ESP) and Authentication Header (AH)&quot;">RFC4835</a>].  IPv6 nodes implementing the
   IPsec Architecture MUST conform to the requirements in [<a href="./rfc4835" title="&quot;Cryptographic Algorithm Implementation Requirements for Encapsulating Security Payload (ESP) and Authentication Header (AH)&quot;">RFC4835</a>].
   Preferred cryptographic algorithms often change more frequently than
   security protocols.  Therefore, implementations MUST allow for
   migration to new algorithms, as <a href="./rfc4835">RFC 4835</a> is replaced or updated in
   the future.

   The current set of mandatory-to-implement algorithms for IKEv2 are
   defined in "Cryptographic Algorithms for Use in the Internet Key
   Exchange Version 2 (IKEv2)" [<a href="./rfc4307" title="&quot;Cryptographic Algorithms for Use in the Internet Key Exchange Version 2 (IKEv2)&quot;">RFC4307</a>].  IPv6 nodes implementing IKEv2
   MUST conform to the requirements in [<a href="./rfc4307" title="&quot;Cryptographic Algorithms for Use in the Internet Key Exchange Version 2 (IKEv2)&quot;">RFC4307</a>] and/or any future
   updates or replacements to [<a href="./rfc4307" title="&quot;Cryptographic Algorithms for Use in the Internet Key Exchange Version 2 (IKEv2)&quot;">RFC4307</a>].

<span class="h2"><a class="selflink" id="section-12" href="#section-12">12</a>.  Router-Specific Functionality</span>

   This section defines general host considerations for IPv6 nodes that
   act as routers.  Currently, this section does not discuss routing-
   specific requirements.

<span class="h3"><a class="selflink" id="section-12.1" href="#section-12.1">12.1</a>.  IPv6 Router Alert Option - <a href="./rfc2711">RFC 2711</a></span>

   The IPv6 Router Alert Option [<a href="./rfc2711" title="&quot;IPv6 Router Alert Option&quot;">RFC2711</a>] is an optional IPv6 Hop-by-Hop
   Header that is used in conjunction with some protocols (e.g., RSVP
   [<a href="./rfc2205" title="&quot;Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification&quot;">RFC2205</a>] or Multicast Listener Discovery (MLD) [<a href="./rfc2710" title="&quot;Multicast Listener Discovery (MLD) for IPv6&quot;">RFC2710</a>]).  The
   Router Alert option will need to be implemented whenever protocols
   that mandate its usage (e.g., MLD) are implemented.  See
   <a href="#section-5.10">Section 5.10</a>.

<span class="h3"><a class="selflink" id="section-12.2" href="#section-12.2">12.2</a>.  Neighbor Discovery for IPv6 - <a href="./rfc4861">RFC 4861</a></span>

   Sending Router Advertisements and processing Router Solicitations
   MUST be supported.

   <a href="./rfc6275#section-7">Section&nbsp;7 of [RFC6275]</a> includes some mobility-specific extensions to
   Neighbor Discovery.  Routers SHOULD implement Sections <a href="#section-7.3">7.3</a> and <a href="#section-7.5">7.5</a>,
   even if they do not implement Home Agent functionality.

<span class="h3"><a class="selflink" id="section-12.3" href="#section-12.3">12.3</a>.  Stateful Address Autoconfiguration (DHCPv6) - <a href="./rfc3315">RFC 3315</a></span>

   A single DHCP server ([<a href="./rfc3315" title="&quot;Dynamic Host Configuration Protocol for IPv6 (DHCPv6)&quot;">RFC3315</a>] or [<a href="./rfc4862" title="&quot;IPv6 Stateless Address Autoconfiguration&quot;">RFC4862</a>]) can provide
   configuration information to devices directly attached to a shared
   link, as well as to devices located elsewhere within a site.
   Communication between a client and a DHCP server located on different
   links requires the use of DHCP relay agents on routers.



<span class="grey">Jankiewicz, et al.            Informational                    [Page 19]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-20" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   In simple deployments, consisting of a single router and either a
   single LAN or multiple LANs attached to the single router, together
   with a WAN connection, a DHCP server embedded within the router is
   one common deployment scenario (e.g., [<a href="./rfc6204" title="&quot;Basic Requirements for IPv6 Customer Edge Routers&quot;">RFC6204</a>]).  However, there is
   no need for relay agents in such scenarios.

   In more complex deployment scenarios, such as within enterprise or
   service provider networks, the use of DHCP requires some level of
   configuration, in order to configure relay agents, DHCP servers, etc.
   In such environments, the DHCP server might even be run on a
   traditional server, rather than as part of a router.

   Because of the wide range of deployment scenarios, support for DHCP
   server functionality on routers is optional.  However, routers
   targeted for deployment within more complex scenarios (as described
   above) SHOULD support relay agent functionality.  Note that "Basic
   Requirements for IPv6 Customer Edge Routers" [<a href="./rfc6204" title="&quot;Basic Requirements for IPv6 Customer Edge Routers&quot;">RFC6204</a>] requires
   implementation of a DHCPv6 server function in IPv6 Customer Edge (CE)
   routers.

<span class="h2"><a class="selflink" id="section-13" href="#section-13">13</a>.  Network Management</span>

   Network management MAY be supported by IPv6 nodes.  However, for IPv6
   nodes that are embedded devices, network management may be the only
   possible way of controlling these nodes.

<span class="h3"><a class="selflink" id="section-13.1" href="#section-13.1">13.1</a>.  Management Information Base (MIB) Modules</span>

   The following two MIB modules SHOULD be supported by nodes that
   support a Simple Network Management Protocol (SNMP) agent.

<span class="h4"><a class="selflink" id="section-13.1.1" href="#section-13.1.1">13.1.1</a>.  IP Forwarding Table MIB</span>

   The IP Forwarding Table MIB [<a href="./rfc4292" title="&quot;IP Forwarding Table MIB&quot;">RFC4292</a>] SHOULD be supported by nodes
   that support an SNMP agent.

<span class="h4"><a class="selflink" id="section-13.1.2" href="#section-13.1.2">13.1.2</a>.  Management Information Base for the Internet Protocol (IP)</span>

   The IP MIB [<a href="./rfc4293" title="&quot;Management Information Base for the Internet Protocol (IP)&quot;">RFC4293</a>] SHOULD be supported by nodes that support an
   SNMP agent.

<span class="h2"><a class="selflink" id="section-14" href="#section-14">14</a>.  Security Considerations</span>

   This document does not directly affect the security of the Internet,
   beyond the security considerations associated with the individual
   protocols.

   Security is also discussed in <a href="#section-11">Section 11</a> above.



<span class="grey">Jankiewicz, et al.            Informational                    [Page 20]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-21" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


<span class="h2"><a class="selflink" id="section-15" href="#section-15">15</a>.  Authors and Acknowledgments</span>

<span class="h3"><a class="selflink" id="section-15.1" href="#section-15.1">15.1</a>.  Authors and Acknowledgments (Current Document)</span>

   For this version of the IPv6 Node Requirements document, the authors
   would like to thank Hitoshi Asaeda, Brian Carpenter, Tim Chown, Ralph
   Droms, Sheila Frankel, Sam Hartman, Bob Hinden, Paul Hoffman, Pekka
   Savola, Yaron Sheffer, and Dave Thaler for their comments.

<span class="h3"><a class="selflink" id="section-15.2" href="#section-15.2">15.2</a>.  Authors and Acknowledgments from <a href="./rfc4279">RFC 4279</a></span>

   The original version of this document (<a href="./rfc4279">RFC 4279</a>) was written by the
   IPv6 Node Requirements design team:

      Jari Arkko
      jari.arkko@ericsson.com

      Marc Blanchet
      marc.blanchet@viagenie.qc.ca

      Samita Chakrabarti
      samita.chakrabarti@eng.sun.com

      Alain Durand
      alain.durand@sun.com

      Gerard Gastaud
      gerard.gastaud@alcatel.fr

      Jun-ichiro Itojun Hagino
      itojun@iijlab.net

      Atsushi Inoue
      inoue@isl.rdc.toshiba.co.jp

      Masahiro Ishiyama
      masahiro@isl.rdc.toshiba.co.jp

      John Loughney
      john.loughney@nokia.com

      Rajiv Raghunarayan
      raraghun@cisco.com

      Shoichi Sakane
      shouichi.sakane@jp.yokogawa.com





<span class="grey">Jankiewicz, et al.            Informational                    [Page 21]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-22" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


      Dave Thaler
      dthaler@windows.microsoft.com

      Juha Wiljakka
      juha.wiljakka@Nokia.com

   The authors would like to thank Ran Atkinson, Jim Bound, Brian
   Carpenter, Ralph Droms, Christian Huitema, Adam Machalek, Thomas
   Narten, Juha Ollila, and Pekka Savola for their comments.  Thanks to
   Mark Andrews for comments and corrections on DNS text.  Thanks to
   Alfred Hoenes for tracking the updates to various RFCs.

<span class="h2"><a class="selflink" id="section-16" href="#section-16">16</a>.  Appendix: Changes from <a href="./rfc4294">RFC 4294</a></span>

   There have been many editorial clarifications as well as significant
   additions and updates.  While this section highlights some of the
   changes, readers should not rely on this section for a comprehensive
   list of all changes.

   1.   Updated the Introduction to indicate that this document is an
        applicability statement and is aimed at general nodes.

   2.   Significantly updated the section on Mobility protocols, adding
        references and downgrading previous SHOULDs to MAYs.

   3.   Changed Sub-IP Layer section to just list relevant RFCs, and
        added some more RFCs.

   4.   Added section on SEND (it is a MAY).

   5.   Revised section on Privacy Extensions [<a href="./rfc4941" title="&quot;Privacy Extensions for Stateless Address Autoconfiguration in IPv6&quot;">RFC4941</a>] to add more
        nuance to recommendation.

   6.   Completely revised IPsec/IKEv2 section, downgrading overall
        recommendation to a SHOULD.

   7.   Upgraded recommendation of DHCPv6 to SHOULD.

   8.   Added background section on DHCP versus RA options, added SHOULD
        recommendation for DNS configuration via RAs [<a href="./rfc6106" title="&quot;IPv6 Router Advertisement Options for DNS Configuration&quot;">RFC6106</a>], and
        cleaned up DHCP recommendations.

   9.   Added recommendation that routers implement Sections <a href="#section-7.3">7.3</a> and <a href="#section-7.5">7.5</a>
        of [<a href="./rfc6275" title="&quot;Mobility Support in IPv6&quot;">RFC6275</a>].

   10.  Added pointer to subnet clarification document [<a href="./rfc5942" title="&quot;IPv6 Subnet Model: The Relationship between Links and Subnet Prefixes&quot;">RFC5942</a>].





<span class="grey">Jankiewicz, et al.            Informational                    [Page 22]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-23" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   11.  Added text that "IPv6 Host-to-Router Load Sharing" [<a href="./rfc4311" title="&quot;IPv6 Host-to-Router Load Sharing&quot;">RFC4311</a>]
        SHOULD be implemented.

   12.  Added reference to [<a href="./rfc5722" title="&quot;Handling of Overlapping IPv6 Fragments&quot;">RFC5722</a>] (Overlapping Fragments), and made
        it a MUST to implement.

   13.  Made "A Recommendation for IPv6 Address Text Representation"
        [<a href="./rfc5952" title="&quot;A Recommendation for IPv6 Address Text Representation&quot;">RFC5952</a>] a SHOULD.

   14.  Removed mention of "DNAME" from the discussion about [<a href="./rfc3363" title="&quot;Representing Internet Protocol version 6 (IPv6) Addresses in the Domain Name System (DNS)&quot;">RFC3363</a>].

   15.  Numerous updates to reflect newer versions of IPv6 documents,
        including [<a href="./rfc4443" title="&quot;Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification&quot;">RFC4443</a>], [<a href="./rfc4291" title="&quot;IP Version 6 Addressing Architecture&quot;">RFC4291</a>], [<a href="./rfc3596" title="&quot;DNS Extensions to Support IP Version 6&quot;">RFC3596</a>], and [<a href="./rfc4213" title="&quot;Basic Transition Mechanisms for IPv6 Hosts and Routers&quot;">RFC4213</a>].

   16.  Removed discussion of "Managed" and "Other" flags in RAs.  There
        is no consensus at present on how to process these flags, and
        discussion of their semantics was removed in the most recent
        update of Stateless Address Autoconfiguration [<a href="./rfc4862" title="&quot;IPv6 Stateless Address Autoconfiguration&quot;">RFC4862</a>].

   17.  Added many more references to optional IPv6 documents.

   18.  Made "A Recommendation for IPv6 Address Text Representation"
        [<a href="./rfc5952" title="&quot;A Recommendation for IPv6 Address Text Representation&quot;">RFC5952</a>] a SHOULD.

   19.  Added reference to [<a href="./rfc5722" title="&quot;Handling of Overlapping IPv6 Fragments&quot;">RFC5722</a>] (Overlapping Fragments), and made
        it a MUST to implement.

   20.  Updated MLD section to include reference to Lightweight MLD
        [<a href="./rfc5790" title="&quot;Lightweight Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols&quot;">RFC5790</a>].

   21.  Added SHOULD recommendation for "Default Router Preferences and
        More-Specific Routes" [<a href="./rfc4191" title="&quot;Default Router Preferences and More-Specific Routes&quot;">RFC4191</a>].

   22.  Made "IPv6 Flow Label Specification" [<a href="./rfc6437" title="&quot;IPv6 Flow Label Specification&quot;">RFC6437</a>] a SHOULD.

<span class="h2"><a class="selflink" id="section-17" href="#section-17">17</a>.  References</span>

<span class="h3"><a class="selflink" id="section-17.1" href="#section-17.1">17.1</a>.  Normative References</span>

   [<a id="ref-RFC1034">RFC1034</a>]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, <a href="./rfc1034">RFC 1034</a>, November 1987.

   [<a id="ref-RFC1035">RFC1035</a>]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, <a href="./rfc1035">RFC 1035</a>, November 1987.

   [<a id="ref-RFC1981">RFC1981</a>]  McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
              for IP version 6", <a href="./rfc1981">RFC 1981</a>, August 1996.




<span class="grey">Jankiewicz, et al.            Informational                    [Page 23]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-24" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   [<a id="ref-RFC2119">RFC2119</a>]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>, March 1997.

   [<a id="ref-RFC2460">RFC2460</a>]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", <a href="./rfc2460">RFC 2460</a>, December 1998.

   [<a id="ref-RFC2671">RFC2671</a>]  Vixie, P., "Extension Mechanisms for DNS (EDNS0)",
              <a href="./rfc2671">RFC 2671</a>, August 1999.

   [<a id="ref-RFC2710">RFC2710</a>]  Deering, S., Fenner, W., and B. Haberman, "Multicast
              Listener Discovery (MLD) for IPv6", <a href="./rfc2710">RFC 2710</a>,
              October 1999.

   [<a id="ref-RFC2711">RFC2711</a>]  Partridge, C. and A. Jackson, "IPv6 Router Alert Option",
              <a href="./rfc2711">RFC 2711</a>, October 1999.

   [<a id="ref-RFC3315">RFC3315</a>]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", <a href="./rfc3315">RFC 3315</a>, July 2003.

   [<a id="ref-RFC3484">RFC3484</a>]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", <a href="./rfc3484">RFC 3484</a>, February 2003.

   [<a id="ref-RFC3590">RFC3590</a>]  Haberman, B., "Source Address Selection for the Multicast
              Listener Discovery (MLD) Protocol", <a href="./rfc3590">RFC 3590</a>,
              September 2003.

   [<a id="ref-RFC3596">RFC3596</a>]  Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
              "DNS Extensions to Support IP Version 6", <a href="./rfc3596">RFC 3596</a>,
              October 2003.

   [<a id="ref-RFC3736">RFC3736</a>]  Droms, R., "Stateless Dynamic Host Configuration Protocol
              (DHCP) Service for IPv6", <a href="./rfc3736">RFC 3736</a>, April 2004.

   [<a id="ref-RFC3810">RFC3810</a>]  Vida, R. and L. Costa, "Multicast Listener Discovery
              Version 2 (MLDv2) for IPv6", <a href="./rfc3810">RFC 3810</a>, June 2004.

   [<a id="ref-RFC4033">RFC4033</a>]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "DNS Security Introduction and Requirements",
              <a href="./rfc4033">RFC 4033</a>, March 2005.

   [<a id="ref-RFC4034">RFC4034</a>]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Resource Records for the DNS Security Extensions",
              <a href="./rfc4034">RFC 4034</a>, March 2005.

   [<a id="ref-RFC4035">RFC4035</a>]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Protocol Modifications for the DNS Security
              Extensions", <a href="./rfc4035">RFC 4035</a>, March 2005.



<span class="grey">Jankiewicz, et al.            Informational                    [Page 24]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-25" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   [<a id="ref-RFC4213">RFC4213</a>]  Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
              for IPv6 Hosts and Routers", <a href="./rfc4213">RFC 4213</a>, October 2005.

   [<a id="ref-RFC4291">RFC4291</a>]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", <a href="./rfc4291">RFC 4291</a>, February 2006.

   [<a id="ref-RFC4292">RFC4292</a>]  Haberman, B., "IP Forwarding Table MIB", <a href="./rfc4292">RFC 4292</a>,
              April 2006.

   [<a id="ref-RFC4293">RFC4293</a>]  Routhier, S., "Management Information Base for the
              Internet Protocol (IP)", <a href="./rfc4293">RFC 4293</a>, April 2006.

   [<a id="ref-RFC4301">RFC4301</a>]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", <a href="./rfc4301">RFC 4301</a>, December 2005.

   [<a id="ref-RFC4303">RFC4303</a>]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              <a href="./rfc4303">RFC 4303</a>, December 2005.

   [<a id="ref-RFC4307">RFC4307</a>]  Schiller, J., "Cryptographic Algorithms for Use in the
              Internet Key Exchange Version 2 (IKEv2)", <a href="./rfc4307">RFC 4307</a>,
              December 2005.

   [<a id="ref-RFC4311">RFC4311</a>]  Hinden, R. and D. Thaler, "IPv6 Host-to-Router Load
              Sharing", <a href="./rfc4311">RFC 4311</a>, November 2005.

   [<a id="ref-RFC4443">RFC4443</a>]  Conta, A., Deering, S., and M. Gupta, "Internet Control
              Message Protocol (ICMPv6) for the Internet Protocol
              Version 6 (IPv6) Specification", <a href="./rfc4443">RFC 4443</a>, March 2006.

   [<a id="ref-RFC4604">RFC4604</a>]  Holbrook, H., Cain, B., and B. Haberman, "Using Internet
              Group Management Protocol Version 3 (IGMPv3) and Multicast
              Listener Discovery Protocol Version 2 (MLDv2) for Source-
              Specific Multicast", <a href="./rfc4604">RFC 4604</a>, August 2006.

   [<a id="ref-RFC4607">RFC4607</a>]  Holbrook, H. and B. Cain, "Source-Specific Multicast for
              IP", <a href="./rfc4607">RFC 4607</a>, August 2006.

   [<a id="ref-RFC4835">RFC4835</a>]  Manral, V., "Cryptographic Algorithm Implementation
              Requirements for Encapsulating Security Payload (ESP) and
              Authentication Header (AH)", <a href="./rfc4835">RFC 4835</a>, April 2007.

   [<a id="ref-RFC4861">RFC4861</a>]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", <a href="./rfc4861">RFC 4861</a>,
              September 2007.

   [<a id="ref-RFC4862">RFC4862</a>]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", <a href="./rfc4862">RFC 4862</a>, September 2007.




<span class="grey">Jankiewicz, et al.            Informational                    [Page 25]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-26" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   [<a id="ref-RFC4941">RFC4941</a>]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", <a href="./rfc4941">RFC 4941</a>, September 2007.

   [<a id="ref-RFC5095">RFC5095</a>]  Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
              of Type 0 Routing Headers in IPv6", <a href="./rfc5095">RFC 5095</a>,
              December 2007.

   [<a id="ref-RFC5453">RFC5453</a>]  Krishnan, S., "Reserved IPv6 Interface Identifiers",
              <a href="./rfc5453">RFC 5453</a>, February 2009.

   [<a id="ref-RFC5722">RFC5722</a>]  Krishnan, S., "Handling of Overlapping IPv6 Fragments",
              <a href="./rfc5722">RFC 5722</a>, December 2009.

   [<a id="ref-RFC5790">RFC5790</a>]  Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet
              Group Management Protocol Version 3 (IGMPv3) and Multicast
              Listener Discovery Version 2 (MLDv2) Protocols", <a href="./rfc5790">RFC 5790</a>,
              February 2010.

   [<a id="ref-RFC5942">RFC5942</a>]  Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet
              Model: The Relationship between Links and Subnet
              Prefixes", <a href="./rfc5942">RFC 5942</a>, July 2010.

   [<a id="ref-RFC5952">RFC5952</a>]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
              Address Text Representation", <a href="./rfc5952">RFC 5952</a>, August 2010.

   [<a id="ref-RFC5996">RFC5996</a>]  Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
              "Internet Key Exchange Protocol Version 2 (IKEv2)",
              <a href="./rfc5996">RFC 5996</a>, September 2010.

   [<a id="ref-RFC6106">RFC6106</a>]  Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
              "IPv6 Router Advertisement Options for DNS Configuration",
              <a href="./rfc6106">RFC 6106</a>, November 2010.

   [<a id="ref-RFC6204">RFC6204</a>]  Singh, H., Beebee, W., Donley, C., Stark, B., and O.
              Troan, "Basic Requirements for IPv6 Customer Edge
              Routers", <a href="./rfc6204">RFC 6204</a>, April 2011.

   [<a id="ref-RFC6437">RFC6437</a>]  Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
              "IPv6 Flow Label Specification", <a href="./rfc6437">RFC 6437</a>, November 2011.

<span class="h3"><a class="selflink" id="section-17.2" href="#section-17.2">17.2</a>.  Informative References</span>

   [<a id="ref-DODv6">DODv6</a>]    DISR IPv6 Standards Technical Working Group, "DoD IPv6
              Standard Profiles For IPv6 Capable Products Version 5.0",
              July 2010,
              &lt;<a href="http://jitc.fhu.disa.mil/apl/ipv6/pdf/disr_ipv6_50.pdf">http://jitc.fhu.disa.mil/apl/ipv6/pdf/disr_ipv6_50.pdf</a>&gt;.




<span class="grey">Jankiewicz, et al.            Informational                    [Page 26]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-27" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   [<a id="ref-POSIX">POSIX</a>]    IEEE, "IEEE Std. 1003.1-2008 Standard for Information
              Technology -- Portable Operating System Interface (POSIX),
              ISO/IEC 9945:2009", &lt;<a href="http://www.ieee.org">http://www.ieee.org</a>&gt;.

   [<a id="ref-RFC0793">RFC0793</a>]  Postel, J., "Transmission Control Protocol", STD 7,
              <a href="./rfc793">RFC 793</a>, September 1981.

   [<a id="ref-RFC2205">RFC2205</a>]  Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", <a href="./rfc2205">RFC 2205</a>, September 1997.

   [<a id="ref-RFC2464">RFC2464</a>]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", <a href="./rfc2464">RFC 2464</a>, December 1998.

   [<a id="ref-RFC2491">RFC2491</a>]  Armitage, G., Schulter, P., Jork, M., and G. Harter, "IPv6
              over Non-Broadcast Multiple Access (NBMA) networks",
              <a href="./rfc2491">RFC 2491</a>, January 1999.

   [<a id="ref-RFC2492">RFC2492</a>]  Armitage, G., Schulter, P., and M. Jork, "IPv6 over ATM
              Networks", <a href="./rfc2492">RFC 2492</a>, January 1999.

   [<a id="ref-RFC2590">RFC2590</a>]  Conta, A., Malis, A., and M. Mueller, "Transmission of
              IPv6 Packets over Frame Relay Networks Specification",
              <a href="./rfc2590">RFC 2590</a>, May 1999.

   [<a id="ref-RFC2675">RFC2675</a>]  Borman, D., Deering, S., and R. Hinden, "IPv6 Jumbograms",
              <a href="./rfc2675">RFC 2675</a>, August 1999.

   [<a id="ref-RFC3146">RFC3146</a>]  Fujisawa, K. and A. Onoe, "Transmission of IPv6 Packets
              over IEEE 1394 Networks", <a href="./rfc3146">RFC 3146</a>, October 2001.

   [<a id="ref-RFC3363">RFC3363</a>]  Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T.
              Hain, "Representing Internet Protocol version 6 (IPv6)
              Addresses in the Domain Name System (DNS)", <a href="./rfc3363">RFC 3363</a>,
              August 2002.

   [<a id="ref-RFC3493">RFC3493</a>]  Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
              Stevens, "Basic Socket Interface Extensions for IPv6",
              <a href="./rfc3493">RFC 3493</a>, February 2003.

   [<a id="ref-RFC3542">RFC3542</a>]  Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei,
              "Advanced Sockets Application Program Interface (API) for
              IPv6", <a href="./rfc3542">RFC 3542</a>, May 2003.

   [<a id="ref-RFC3678">RFC3678</a>]  Thaler, D., Fenner, B., and B. Quinn, "Socket Interface
              Extensions for Multicast Source Filters", <a href="./rfc3678">RFC 3678</a>,
              January 2004.




<span class="grey">Jankiewicz, et al.            Informational                    [Page 27]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-28" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   [<a id="ref-RFC3776">RFC3776</a>]  Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to
              Protect Mobile IPv6 Signaling Between Mobile Nodes and
              Home Agents", <a href="./rfc3776">RFC 3776</a>, June 2004.

   [<a id="ref-RFC3971">RFC3971</a>]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
              Neighbor Discovery (SEND)", <a href="./rfc3971">RFC 3971</a>, March 2005.

   [<a id="ref-RFC3972">RFC3972</a>]  Aura, T., "Cryptographically Generated Addresses (CGA)",
              <a href="./rfc3972">RFC 3972</a>, March 2005.

   [<a id="ref-RFC4191">RFC4191</a>]  Draves, R. and D. Thaler, "Default Router Preferences and
              More-Specific Routes", <a href="./rfc4191">RFC 4191</a>, November 2005.

   [<a id="ref-RFC4302">RFC4302</a>]  Kent, S., "IP Authentication Header", <a href="./rfc4302">RFC 4302</a>,
              December 2005.

   [<a id="ref-RFC4338">RFC4338</a>]  DeSanti, C., Carlson, C., and R. Nixon, "Transmission of
              IPv6, IPv4, and Address Resolution Protocol (ARP) Packets
              over Fibre Channel", <a href="./rfc4338">RFC 4338</a>, January 2006.

   [<a id="ref-RFC4380">RFC4380</a>]  Huitema, C., "Teredo: Tunneling IPv6 over UDP through
              Network Address Translations (NATs)", <a href="./rfc4380">RFC 4380</a>,
              February 2006.

   [<a id="ref-RFC4429">RFC4429</a>]  Moore, N., "Optimistic Duplicate Address Detection (DAD)
              for IPv6", <a href="./rfc4429">RFC 4429</a>, April 2006.

   [<a id="ref-RFC4584">RFC4584</a>]  Chakrabarti, S. and E. Nordmark, "Extension to Sockets API
              for Mobile IPv6", <a href="./rfc4584">RFC 4584</a>, July 2006.

   [<a id="ref-RFC4821">RFC4821</a>]  Mathis, M. and J. Heffner, "Packetization Layer Path MTU
              Discovery", <a href="./rfc4821">RFC 4821</a>, March 2007.

   [<a id="ref-RFC4877">RFC4877</a>]  Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with
              IKEv2 and the Revised IPsec Architecture", <a href="./rfc4877">RFC 4877</a>,
              April 2007.

   [<a id="ref-RFC4884">RFC4884</a>]  Bonica, R., Gan, D., Tappan, D., and C. Pignataro,
              "Extended ICMP to Support Multi-Part Messages", <a href="./rfc4884">RFC 4884</a>,
              April 2007.

   [<a id="ref-RFC4944">RFC4944</a>]  Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
              "Transmission of IPv6 Packets over IEEE 802.15.4
              Networks", <a href="./rfc4944">RFC 4944</a>, September 2007.

   [<a id="ref-RFC5006">RFC5006</a>]  Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
              "IPv6 Router Advertisement Option for DNS Configuration",
              <a href="./rfc5006">RFC 5006</a>, September 2007.



<span class="grey">Jankiewicz, et al.            Informational                    [Page 28]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-29" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


   [<a id="ref-RFC5014">RFC5014</a>]  Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6
              Socket API for Source Address Selection", <a href="./rfc5014">RFC 5014</a>,
              September 2007.

   [<a id="ref-RFC5072">RFC5072</a>]  S.Varada, Haskins, D., and E. Allen, "IP Version 6 over
              PPP", <a href="./rfc5072">RFC 5072</a>, September 2007.

   [<a id="ref-RFC5121">RFC5121</a>]  Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S.
              Madanapalli, "Transmission of IPv6 via the IPv6
              Convergence Sublayer over IEEE 802.16 Networks", <a href="./rfc5121">RFC 5121</a>,
              February 2008.

   [<a id="ref-RFC5555">RFC5555</a>]  Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
              Routers", <a href="./rfc5555">RFC 5555</a>, June 2009.

   [<a id="ref-RFC6275">RFC6275</a>]  Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
              in IPv6", <a href="./rfc6275">RFC 6275</a>, July 2011.

   [<a id="ref-USGv6">USGv6</a>]    National Institute of Standards and Technology, "A Profile
              for IPv6 in the U.S. Government - Version 1.0", July 2008,
              &lt;<a href="http://www.antd.nist.gov/usgv6/usgv6-v1.pdf">http://www.antd.nist.gov/usgv6/usgv6-v1.pdf</a>&gt;.






























<span class="grey">Jankiewicz, et al.            Informational                    [Page 29]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-30" ></span>
<span class="grey"><a href="./rfc6434">RFC 6434</a>                 IPv6 Node Requirements            December 2011</span>


Authors' Addresses

   Ed Jankiewicz
   SRI International, Inc.
   333 Ravenswood Ave.
   Menlo Park, CA  94025
   USA

   Phone: +1 443 502 5815
   EMail: edward.jankiewicz@sri.com


   John Loughney
   Nokia
   200 South Mathilda Ave.
   Sunnyvale, CA  94086
   USA

   Phone: +1 650 283 8068
   EMail: john.loughney@nokia.com


   Thomas Narten
   IBM Corporation
   3039 Cornwallis Ave.
   PO Box 12195
   Research Triangle Park, NC  27709-2195
   USA

   Phone: +1 919 254 7798
   EMail: narten@us.ibm.com




















Jankiewicz, et al.            Informational                    [Page 30]
</pre>