Simple Provisioning of Public Names for Residential Networks
draft-ietf-homenet-front-end-naming-delegation-15

Document Type Active Internet-Draft (homenet WG)
Authors Daniel Migault  , Ralf Weber  , Michael Richardson  , Ray Hunter 
Last updated 2021-05-13 (latest revision 2021-04-28)
Replaces draft-mglt-homenet-front-end-naming-delegation
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Homenet                                                       D. Migault
Internet-Draft                                                  Ericsson
Intended status: Standards Track                                R. Weber
Expires: November 14, 2021                                       Nominum
                                                           M. Richardson
                                                Sandelman Software Works
                                                               R. Hunter
                                                    Globis Consulting BV
                                                            May 13, 2021

      Simple Provisioning of Public Names for Residential Networks
           draft-ietf-homenet-front-end-naming-delegation-15

Abstract

   Home owners often have IPv6 devices that they wish to access over the
   Internet using names.
   Outsourcing the DNS servers to a DNS infrastructure protects against
   possible DDoS attacks as well as sudden renumbering of the home
   network.  It has been possible to register and populate a DNS Zone
   with names since DNS became a thing, but it has been an activity
   typically reserved for experts.  This document automates the process
   through creation of a Homenet Naming Authority (HNA), whose
   responsibility is to select, sign and publish names to a set of
   publicly visible servers.

   This document describes the mechanism that enables the HNA to
   outsource the naming service to the DNS Outsourcing Infrastructure
   (DOI) via a Distribution Manager (DM).

   In addition, this document deals with publication of a corresponding
   reverse zone.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

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   This Internet-Draft will expire on November 14, 2021.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Selecting Names to Publish  . . . . . . . . . . . . . . .   5
     1.2.  Alternative solutions . . . . . . . . . . . . . . . . . .   6
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   7
   3.  Architecture Description  . . . . . . . . . . . . . . . . . .   8
     3.1.  Architecture Overview . . . . . . . . . . . . . . . . . .   8
     3.2.  Distribution Manager Communication Channels . . . . . . .  11
   4.  Control Channel . . . . . . . . . . . . . . . . . . . . . . .  12
     4.1.  Information to Build the Public Homenet Zone  . . . . . .  13
     4.2.  Information to build the DNSSEC chain of trust  . . . . .  13
     4.3.  Information to set the Synchronization Channel  . . . . .  14
     4.4.  Deleting the delegation . . . . . . . . . . . . . . . . .  14
     4.5.  Messages Exchange Description . . . . . . . . . . . . . .  14
       4.5.1.  Retrieving information for the Public Homenet Zone. .  14
       4.5.2.  Providing information for the DNSSEC chain of trust .  15
       4.5.3.  Providing information for the Synchronization Channel  16
       4.5.4.  HNA instructing deleting the delegation . . . . . . .  17
     4.6.  Securing the Control Channel  . . . . . . . . . . . . . .  17
     4.7.  Implementation Concerns . . . . . . . . . . . . . . . . .  18
   5.  Synchronization Channel . . . . . . . . . . . . . . . . . . .  19
     5.1.  Securing the Synchronization Channel  . . . . . . . . . .  20
   6.  DM Distribution Channel . . . . . . . . . . . . . . . . . . .  20
   7.  HNA Security Policies . . . . . . . . . . . . . . . . . . . .  20
   8.  DNSSEC compliant Homenet Architecture . . . . . . . . . . . .  21
   9.  Homenet Reverse Zone Channels Configuration . . . . . . . . .  21
   10. Homenet Public Zone Channel Configurations  . . . . . . . . .  22
   11. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . .  24
     11.1.  Hidden Primary . . . . . . . . . . . . . . . . . . . . .  24
   12. Privacy Considerations  . . . . . . . . . . . . . . . . . . .  25

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   13. Security Considerations . . . . . . . . . . . . . . . . . . .  26
     13.1.  HNA DM channels  . . . . . . . . . . . . . . . . . . . .  26
     13.2.  Names are less secure than IP addresses  . . . . . . . .  26
     13.3.  Names are less volatile than IP addresses  . . . . . . .  27
   14. Information Model for Outsourced information  . . . . . . . .  27
     14.1.  Outsourced Information Model . . . . . . . . . . . . . .  28
   15. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  30
   16. Acknowledgment  . . . . . . . . . . . . . . . . . . . . . . .  30
   17. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  30
   18. References  . . . . . . . . . . . . . . . . . . . . . . . . .  31
     18.1.  Normative References . . . . . . . . . . . . . . . . . .  31
     18.2.  Informative References . . . . . . . . . . . . . . . . .  34
   Appendix A.  Envisioned deployment scenarios  . . . . . . . . . .  36
     A.1.  CPE Vendor  . . . . . . . . . . . . . . . . . . . . . . .  36
     A.2.  Agnostic CPE  . . . . . . . . . . . . . . . . . . . . . .  36
   Appendix B.  Example: A manufacturer provisioned HNA product flow  37
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  38

1.  Introduction

   The Homenet Naming Authority (HNA) is responsible for making devices
   within the home network accessible by a public name within the home
   network as well as from outside the home network (e.g. the Internet).
   IPv6 connectivity provides the possibility of global end to end IP
   connectivity.

   The use of a DNS zone for each home network is a reasonable and
   scalable way to make the set of public names visible.  There are a
   number of ways to populate such a zone.  This specification proposes
   a way based on a number of assumptions about typical home networks.

   1.  The names of the devices accessible from the Internet are stored
       in the Public Homenet Zone, served by a DNS authoritative server.

   2.  It is unlikely that home networks will contain sufficiently
       robust platforms designed to host and expose to the Internet a
       service such as the DNS and as such would expose the home network
       to DDoS attacks.

   3.  [RFC7368] emphasizes that the home network is subject to
       connectivity disruptions with the ISP.  But, names used within
       the home MUST be resilient against such disruption.

   This specification makes the public names resolvable within both the
   home network and on the Internet, even when there are disruptions.

   This is achieved by having a function inside the home network that
   builds, signs, publishes, and manages a Public Homenet Zone, thus

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   providing bindings between public names, IP addresses, and other RR
   types.

   The management of the names can be under the responsibility the
   Customer Premises Equipment (CPE) does.  Other devices within the
   home network could fulfill this role e.g. a Network Attached Storage
   server, but for simplicity, this document assumes the function is
   located on one of the CPE devices.

   The homenet architecture [RFC7368] makes it clear that a home network
   may have multiple CPEs.  The management of the Public Homenet Zone
   involves DNS specific mechanisms that cannot be distributed over
   multiple servers (primary server), when multiple nodes can
   potentially manage the Public Homenet Zone, a single node needs to be
   selected per outsourced zone.  This selected node is designated as
   providing the HNA function.

   The process by which a single HNA is selected per zone is not in
   scope for this document.  It is envisioned that a future document
   will describe an HNCP mechanism to elect the single HNA.

   CPEs, which may host the HNA function are usually low powered devices
   not designed for supporting a heavy traffic.  As a result, hosting an
   authoritative DNS service visible to the Internet may expose the home
   network to resource exhaustion and other attacks.  On the other hand,
   if the only copy of the public zone is on the Internet, then Internet
   connectivity disruptions would make the names unavailable inside the
   homenet.

   In order to avoid resource exhaustion and other attacks, this
   document describes in Section 3.1 an architecture that outsources the
   authoritative naming service of the home network.  More specifically,
   the HNA builds the Public Homenet Zone and outsources it to a DNS
   Outsourcing Infrastructure (DOI) via a Distribution Manager (DM).
   The DOI is in charge of publishing the corresponding Public Homenet
   Zone on the Internet.  The transfer of DNS zone information is
   achieved using standard DNS mechanisms involving primary and
   secondary DNS servers, with the HNA being a stealth primary, and the
   DM a secondary.

   In order to keep the Public Homenet Zone up-to-date Section 5
   describes how the HNA and the DOI synchronize the Pubic Homenet Zone.

   The architecture is explicitly designed to enable fully functional
   DNSSEC, and the Public Homenet Zone is expected to be signed with a
   secure delegation.  DNSSEC key management and zone signing are
   handled by the HNA.

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   Section 10 discusses management and configuration of the Public
   Homenet Zone.  It shows that the HNA configuration of the DOI can
   involve no or little interaction with the end user.  More
   specifically, it shows that the existence of an account in the DOI is
   sufficient for the DOI to push the necessary configuration.  In
   addition, when the DOI and CPE are both managed by an ISP, the
   configuration can be entirely automated - see Section 9.

   Section 9 discusses management of one or more reverse zones.  It
   shows that management of the reverse zones can be entirely automated
   and benefit from a pre-established relation between the ISP and the
   home network.  Note that such scenarios may also be met for the
   Public Homenet Zone.

   Section 11 discusses how renumbering should be handled.  Finally,
   Section 12 and Section 13 respectively discuss privacy and security
   considerations when outsourcing the Public Homenet Zone.

   The Public Homenet Zone is expected to contain public information
   only in a single universal view.  This document does not define how
   the information required to construct this view is derived.

   It is also not in the scope of this document to define names for
   exclusive use within the boundaries of the local home network.
   Instead, local scope information is expected to be provided to the
   home network using local scope naming services. mDNS [RFC6762] and
   DNS-SD [RFC6763] are two examples of these services.  Currently mDNS
   is limited to a single link network.  However, future protocols and
   architectures [I-D.ietf-homenet-simple-naming] are expected to
   leverage this constraint as pointed out in [RFC7558].

1.1.  Selecting Names to Publish

   While this document does not create any normative mechanism by which
   the selection of names to publish, this document anticipates that the
   home network administrator (a humuan), will be presented with a list
   of current names and addresses present on the inside of the home
   network.

   The administrator would mark which devices (by name), are to be
   published.  The HNA would then collect the IPv6 address(es)
   associated with that device, and put the name into the Public Homenet
   Zone.  The address of the device can be collected from a number of
   places: mDNS [RFC6762], DHCP [RFC6644], UPnP, PCP [RFC6887], or
   manual configuration.

   A device may have a Global Unicast Address (GUA), a Unique Local IPv6
   Address (ULA), as as well IPv6-Link-Local addresses, IPv4-Link-Local

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   Addresses, and RFC1918 addresses.  Of these the link-local are never
   useful for the Public Zone, and should be omitted.  The IPv6 ULA and
   the RFC1918 addresses may be useful to publish, if the home network
   environment features a VPN that would allow the home owner to reach
   the network.

   The IPv6 ULA addressees are significantly safer to publish, as the
   RFC1918 addressees are likely to be confusing to any other entity.

   In general, one expects the GUA to be the default address to be
   published.  However, during periods when the home network has
   connectivity problems, the ULA and RFC1918 addressees can be used
   inside the home, and the mapping from public name to locally useful
   location address would permit many services secured with HTTPS to
   continue to operate.

1.2.  Alternative solutions

   An alternative existing solution in IPv4 is to have a single zone,
   where a host uses a RESTful HTTP service to register a single name
   into a common public zone.  This is often called "Dynamic DNS", and
   there are a number of commercial providers, including Dyn, Gandi etc.
   These solutions were typically used by a host behind the CPE to make
   its CPE IPv4 address visible, usually in order to enable incoming
   connections.  This is the most common scenario considered in this
   section, while some variant may also consider the client being hosted
   in the CPE.

   For a very few number (one to three) of hosts, the use of such a
   system provides an alternative to the architecture described in this
   document.  The alternative - even adapted to IPv6 and ignoring those
   associated to an IPv4 development - does suffer from some severe
   limitations:

   o  the CPE/HNA router is unaware of the process, and cannot respond
      to queries for these names when there are disruptions in
      connectivity.  This makes the home user or application dependent
      on having to resolve different names in the event of outages or
      disruptions.

   o  the CPE/HNA router cannot control the process.  Any host can do
      this regardless of whether or not the home network administrator
      wants the name published or not.  There is therefore no possible
      audit trail.

   o  the credentials for the dynamic DNS server need to be securely
      transferred to all hosts that wish to use it.  This is not a
      problem for a technical user to do with one or two hosts, but it

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      does not scale to multiple hosts and becomes a problem for non-
      technical users.

   o  "all the good names are taken" - current services put everyone's
      names into some small set of zones, and there are often conflicts.
      Distinguishing similar names by delegation of zones was among the
      primary design goals of the DNS system.

   o  The RESTful services do not always support all RR types.  The
      homenet user is dependent on the service provider supporting new
      types.  By providing full DNS delegation, this document enables
      all RR types and also future extensions.

   There is no technical reason why a RESTful service could not provide
   solutions to many of these problems, but this document describes a
   DNS-based solution.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   Customer Premises Equipment:  (CPE) is a router providing
      connectivity to the home network.

   Homenet Zone:  is the DNS zone for use within the boundaries of the
      home network: 'home.arpa' (see [RFC8375]).  This zone is not
      considered public and is out of scope for this document.

   Registered Homenet Domain:  is the domain name that is associated
      with the home network.

   Public Homenet Zone:  contains the names in the home network that are
      expected to be publicly resolvable on the Internet.

   Homenet Naming Authority(HNA): is a function responsible for managing
   the Public Homenet Zone.  This includes populating the Public Homenet
   Zone, signing the zone for DNSSEC, as well as managing the
   distribution of that Homenet Zone to the DNS Outsourcing
   Infrastructure (DOI).

   DNS Outsourcing Infrastructure (DOI):  is the infrastructure
      responsible for receiving the Public Homenet Zone and publishing
      it on the Internet.  It is mainly composed of a Distribution
      Manager and Public Authoritative Servers.

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   Public Authoritative Servers:  are the authoritative name servers for
      the Public Homenet Zone.  Name resolution requests for the Homenet
      Domain are sent to these servers.  For resiliency the Public
      Homenet Zone SHOULD be hosted on multiple servers.

   Homenet Authoritative Servers:  are authoritative name servers within
      the Homenet network.

   Distribution Manager (DM):  is the (set of) server(s) to which the
      HNA synchronizes the Public Homenet Zone, and which then
      distributes the relevant information to the Public Authoritative
      Servers.

   Homenet Reverse Zone:  The reverse zone file associated with the
      Public Homenet Zone.

   Reverse Public Authoritative Servers:  equivalent to Public
      Authoritative Servers specifically for reverse resolution.

   Reverse Distribution Manager:  equivalent to Distribution Manager
      specifically for reverse resolution.

   Homenet DNSSEC Resolver:  a resolver that performs a DNSSEC
      resolution on the home network for the Public Homenet Zone.  The
      resolution is performed requesting the Homenet Authoritative
      Servers.

   DNSSEC Resolver:  a resolver that performs a DNSSEC resolution on the
      Internet for the Public Homenet Zone.  The resolution is performed
      requesting the Public Authoritative Servers.

3.  Architecture Description

   This section provides an overview of the architecture for outsourcing
   the authoritative naming service from the HNA to the DOI.  Note that
   Section 14 defines necessary parameter to configure the HNA.

3.1.  Architecture Overview

   Figure 1 illustrates the architecture where the HNA outsources the
   publication of the Public Homenet Zone to the DOI.

   The Public Homenet Zone is identified by the Registered Homenet
   Domain Name - myhome.example.  The ".local" as well as ".home.arpa"
   are explicitly not considered as Public Homenet zones and represented
   as Homenet Zone in Figure 1.

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   The HNA SHOULD build the Public Homenet Zone in a single view
   populated with all resource records that are expected to be published
   on the Internet.  The HNA also signs the Public Homenet Zone.  The
   HNA handles all operations and keying material required for DNSSEC,
   so there is no provision made in this architecture for transferring
   private DNSSEC related keying material between the HNA and the DM.

   Once the Public Homenet Zone has been built, the HNA outsources it to
   the DOI as described in Figure 1.  The HNA acts as a hidden primary
   [RFC8499] while the DM behaves as a secondary responsible to
   distribute the Public Homenet Zone to the multiple Public
   Authoritative Servers that DOI is responsible for.  The DM has three
   communication channels:

   o  a DM Control Channel (Section 4) to configure the HNA and the DOI,

   o  a DM Synchronization Channel (Section 5) to synchronize the Public
      Homenet Zone on the HNA and on the DM,

   o  one or more Distribution Channels (Section 6 that distribute the
      Public Homenet Zone from the DM to the Public Authoritative Server
      serving the Public Homenet Zone on the Internet.

   There might be multiple DM's, and multiple servers per DM.  This
   document assumes a single DM server for simplicity, but there is no
   reason why each channel needs to be implemented on the same server or
   use the same code base.

   It is important to note that while the HNA is configured as an
   authoritative server, it is not expected to answer to DNS requests
   from the public Internet for the Public Homenet Zone.  More
   specifically, the addresses associated with the HNA SHOULD NOT be
   mentioned in the NS records of the Public Homenet zone, unless
   additional security provisions necessary to protect the HNA from
   external attack have been taken.

   The DOI is also responsible for ensuring the DS record has been
   updated in the parent zone.

   Resolution is performed by the DNSSEC resolvers.  When the resolution
   is performed outside the home network, the DNSSEC Resolver resolves
   the DS record on the Global DNS and the name associated to the Public
   Homenet Zone (myhome.example) on the Public Authoritative Servers.

   When the resolution is performed from within the home network, the
   Homenet DNSSEC Resolver MAY proceed similarly.  On the other hand, to
   provide resilience to the Public Homenet Zone in case of WAN
   connectivity disruption, the Homenet DNSSEC Resolver SHOULD be able

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   to perform the resolution on the Homenet Authoritative Servers.
   These servers are not expected to be mentioned in the Public Homenet
   Zone, nor to be accessible from the Internet.  As such their
   information as well as the corresponding signed DS record MAY be
   provided by the HNA to the Homenet DNSSEC Resolvers, e.g., using HNCP
   [RFC7788].  Such configuration is outside the scope of this document.
   Since the scope of the Homenet Authoritative Servers is limited to
   the home network, these servers are expected to serve the Homenet
   Zone as represented in Figure 1.

   How the Homenet Authoritative Servers are provisioned is also out of
   scope of this specification.  It could be implemented using primary
   and secondary servers, or via rsync.  In some cases, the HNA and
   Homenet Authoritative Servers may be combined together which would
   result in a common instantiation of an authoritative server on the
   WAN and inner homenet interface.  Note that [RFC6092] REC-8 states
   this must not be the default configuration.  Other mechanisms may
   also be used.

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          Home network                 |         Internet
                                       |
                                       | +----------------------------+
                                       | |          DOI               |
                             Control   | |                            |
   +-----------------------+ Channel   | |  +-----------------------+ |
   |         HNA           |<-------------->| Distribution Manager  | |
   |+---------------------+|           | |  |+---------------------+| |
   || Public Homenet Zone ||Synchronization || Public Homenet Zone || |
   ||   (myhome.example)  || Channel   | |  ||  (myhome.example)   || |
   |+---------------------+|<-------------->|+---------------------+| |
   +-----------^-----------+           | |  +-----------------------+ |
               .                       | |           ^ Distribution   |
               .                       | |           | Channel        |
   +-----------v-----------+           | |           v                |
   | Homenet Authoritative |           | |  +-----------------------+ |
   | Server(s)             |           | |  | Public Authoritative  | |
   |+---------------------+|           | |  | Server(s)             | |
   ||Public Homenet Zone  ||           | |  |+---------------------+| |
   ||  (myhome.example)   ||           | |  || Public Homenet Zone || |
   |+---------------------+|           | |  ||  (myhome.example)   || |
   ||     Homenet Zone    ||           | |  |+---------------------+| |
   ||     (home.arpa)     ||           | |  +-----------------------+ |
   |+---------------------+|           | +----------^---|-------------+
   +----------^---|--------+           |            |   |
              |   |           name resolution       |   |
              |   v                    |            |   v
    +----------------------+           | +-----------------------+
    |       Homenet        |           | |       Internet        |
    |    DNSSEC Resolver   |           | |    DNSSEC Resolver    |
    +----------------------+           | +-----------------------+

                   Figure 1: Homenet Naming Architecture

3.2.  Distribution Manager Communication Channels

   This section details the DM channels, that is the Control Channel,
   the Synchronization Channel and the Distribution Channel.

   The Control Channel and the Synchronization Channel are the
   interfaces used between the HNA and the DOI.  The entity within the
   DOI responsible to handle these communications is the DM and
   communications between the HNA and the DM MUST be protected and
   mutually authenticated.  While Section 4.6 discusses in more depth
   the different security protocols that could be used to secure, it is
   RECOMMENDED to use TLS with mutually authentication based on
   certificates to secure the channel between the HNA and the DM.

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   The Control Channel is used to set up the Synchronization Channel.
   We assume that the HNA initiates the Control Channel connection with
   the DM and as such has a prior knowledge of the DM identity (X509
   certificate), the IP address and port number to use and protocol to
   set secure session.  We also assume the DM has knowledge of the
   identity of the HNA (X509 certificate) as well as the Registered
   Homenet Domain.  For more detail to see how this can be achieved,
   please see Section 10.

   The information exchanged between the HNA and the DM uses DNS
   messages protected by DNS over TLS (DoT) [RFC7858].  Other
   specifications may consider protecting DNS messages with other
   transport layers, among others, DNS over DTLS [RFC8094], or DNS over
   HTTPs (DoH) [RFC8484] or DNS over QUIC [I-D.ietf-dprive-dnsoquic].
   There was consideration to using a standard TSIG [RFC2845] or SIG(0)
   [RFC2931] to perform a dynamic DNS update to the DM.  There are a
   number of issues with this.  The first one is that TSIG or SIG(0)
   make scenarios where the end user needs to interact via its web
   browser more complex.  More precisely, authorization and access
   control granted via OAUTH would be unnecessarily complex with TSIG or
   SIG(0).

   The main issue is that the Dynamic DNS update would also update the
   parent zone's (NS, DS and associated A or AAAA records) while the
   goal is to update the DM configuration files.  The visible NS records
   SHOULD remain pointing at the cloud provider's anycast addresses.
   Revealing the address of the HNA in the DNS is not desirable.  Refer
   to Section 4.2 for more details.

   This specification assumes:

   o  the DM serves both the Control Channel and Synchronization Channel
      on a single IP address, single port and using a single transport
      protocol.

   o  By default, the HNA uses a single IP address for both the Control
      and Synchronization channel.  However, the HNA MAY use distinct IP
      addresses for the Control Channel and the Synchronization Channel
      - see Section 5 and Section 4.3 for more details.

   The Distribution Channel is internal to the DOI and as such is not
   the primary concern of this specification.

4.  Control Channel

   The DM Control Channel is used by the HNA and the DOI to exchange
   information related to the configuration of the delegation which
   includes information to build the Public Homenet Zone (Section 4.1),

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   information to build the DNSSEC chain of trust (Section 4.2) and
   information to set the Synchronization Channel (Section 4.3).

4.1.  Information to Build the Public Homenet Zone

   When the HNA builds the Public Homenet Zone, it must include
   information that it retrieves from the DM relating to how the zone is
   to be published.

   The information includes at least names and IP addresses of the
   Public Authoritative Name Servers.  In term of RRset information this
   includes:

   o  the MNAME of the SOA,

   o  the NS and associated A and AAA RRsets of the name servers.

   The DOI MAY also provide operational parameters such as other fields
   of SOA (SERIAL, RNAME, REFRESH, RETRY, EXPIRE and MINIMUM).  As the
   information is necessary for the HNA to proceed and the information
   is associated to the DOI, this information exchange is mandatory.

4.2.  Information to build the DNSSEC chain of trust

   The HNA SHOULD provide the hash of the KSK (DS RRset), so the that
   DOI provides this value to the parent zone.  A common deployment use
   case is that the DOI is the registrar of the Registered Homenet
   Domain, and as such, its relationship with the registry of the parent
   zone enables it to update the parent zone.  When such relation
   exists, the HNA should be able to request the DOI to update the DS
   RRset in the parent zone.  A direct update is especially necessary to
   initialize the chain of trust.

   Though the HNA may also later directly update the values of the DS
   via the Control Channel, it is RECOMMENDED to use other mechanisms
   such as CDS and CDNSKEY [RFC7344] for transparent updates during key
   roll overs.

   As some deployments may not provide a DOI that will be able to update
   the DS in the parent zone, this information exchange is OPTIONAL.

   By accepting the DS RR, the DM commits in taking care of advertising
   the DS to the parent zone.  Upon refusal, the DM clearly indicates it
   does not have the capacity to proceed to the update.

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4.3.  Information to set the Synchronization Channel

   The HNA works as a primary authoritative DNS server, while the DM
   works like a secondary.  As a result, the HNA MUST provide the IP
   address the DM is using to reach the HNA.  The synchronization
   Channel will be set between that IP address and the IP address of the
   DM.  By default, the IP address used by the HNA in the Control
   Channel is considered by the DM and the specification of the IP by
   the HNA is only OPTIONAL.  The transport channel (including port
   number) is the same as the one used between the HNA and the DM for
   the Control Channel.

4.4.  Deleting the delegation

   The purpose of the previous sections were to exchange information in
   order to set a delegation.  The HNA MUST also be able to delete a
   delegation with a specific DM.  Upon an instruction of deleting the
   delegation, the DM MUST stop serving the Public Homenet Zone.

4.5.  Messages Exchange Description

   There are multiple ways this information could be exchanged between
   the HNA and the DM.  This specification defines a mechanism that re-
   use the DNS exchanges format.  The intention is to reuse standard
   libraries especially to check the format of the exchanged fields as
   well as to minimize the additional libraries needed for the HNA.  The
   re-use of DNS exchanges achieves these goals.  Note that while
   information is provided using DNS exchanges, the exchanged
   information is not expected to be set in any zone file, instead this
   information is uses as commands between the HNA and the DM.

   The Control Channel is not expected to be a long term session.  After
   a predefined timer - similar to those used for TCP - the Control
   Channel is expected to be terminated - by closing the transport
   channel.  The Control Channel MAY be re-opened at any time later.

   The provisioning process SHOULD provide a method of securing the
   Control Channel, so that the content of messages can be
   authenticated.  This authentication MAY be based on certificates for
   both the DM and each HNA.  The DM may also create the initial
   configuration for the delegation zone in the parent zone during the
   provisioning process.

4.5.1.  Retrieving information for the Public Homenet Zone.

   The information provided by the DM to the HNA is retrieved by the HNA
   with an AXFR exchange [RFC1034].  AXFR enables the response to
   contain any type of RRsets.  The response might be extended in the

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   future if additional information will be needed.  Alternatively, the
   information provided by the HNA to the DM is pushed by the HNA via a
   DNS update exchange [RFC2136].

   To retrieve the necessary information to build the Public Homenet
   Zone, the HNA MUST send a DNS request of type AXFR associated to the
   Registered Homenet Domain.  The DM MUST respond with a zone template.
   The zone template MUST contain a RRset of type SOA, one or multiple
   RRset of type NS and zero or more RRset of type A or AAAA.

   o  The SOA RR indicates to the HNA the value of the MNAME of the
      Public Homenet Zone.

   o  The NAME of the SOA RR MUST be the Registered Homenet Domain.

   o  The MNAME value of the SOA RDATA is the value provided by the DOI
      to the HNA.

   o  Other RDATA values (RNAME, REFRESH, RETRY, EXPIRE and MINIMUM) are
      provided by the DOI as suggestions.

   The NS RRsets carry the Public Authoritative Servers of the DOI.
   Their associated NAME MUST be the Registered Homenet Domain.

   The TTL and RDATA are those expected to be published on the Public
   Homenet Zone.  The RRsets of Type A and AAAA MUST have their NAME
   matching the NSDNAME of one of the NS RRsets.

   Upon receiving the response, the HNA MUST validate format and
   properties of the SOA, NS and A or AAAA RRsets.  If an error occurs,
   the HNA MUST stop proceeding and MUST log an error.  Otherwise, the
   HNA builds the Public Homenet Zone by setting the MNAME value of the
   SOA as indicated by the SOA provided by the AXFR response.  The HNA
   SHOULD set the value of NAME, REFRESH, RETRY, EXPIRE and MINIMUM of
   the SOA to those provided by the AXFR response.  The HNA MUST insert
   the NS and corresponding A or AAAA RRset in its Public Homenet Zone.
   The HNA MUST ignore other RRsets.  If an error message is returned by
   the DM, the HNA MUST proceed as a regular DNS resolution.  Error
   messages SHOULD be logged for further analysis.  If the resolution
   does not succeed, the outsourcing operation is aborted and the HNA
   MUST close the Control Channel.

4.5.2.  Providing information for the DNSSEC chain of trust

   To provide the DS RRset to initialize the DNSSEC chain of trust the
   HNA MAY send a DNS update [RFC2136] message.

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   The DNS update message is composed of a Header section, a Zone
   section, a Pre-requisite section, and Update section and an
   additional section.  The Zone section MUST set the ZNAME to the
   parent zone of the Registered Homenet Domain - that is where the DS
   records should be inserted.  As described [RFC2136], ZTYPE is set to
   SOA and ZCLASS is set to the zone's class.  The Pre-requisite section
   MUST be empty.  The Update section is a DS RRset with its NAME set to
   the Registered Homenet Domain and the associated RDATA corresponds to
   the value of the DS.  The Additional Data section MUST be empty.

   Though the pre-requisite section MAY be ignored by the DM, this value
   is fixed to remain coherent with a standard DNS update.

   Upon receiving the DNS update request, the DM reads the DS RRset in
   the Update section.  The DM checks ZNAME corresponds to the parent
   zone.  The DM SHOULD ignore non empty the Pre-requisite and
   Additional Data section.  The DM MAY update the TTL value before
   updating the DS RRset in the parent zone.  Upon a successful update,
   the DM should return a NOERROR response as a commitment to update the
   parent zone with the provided DS.  An error indicates the MD does not
   update the DS, and other method should be used by the HNA.

   The regular DNS error message SHOULD be returned to the HNA when an
   error occurs.  In particular a FORMERR is returned when a format
   error is found, this includes when unexpected RRSets are added or
   when RRsets are missing.  A SERVFAIL error is returned when a
   internal error is encountered.  A NOTZONE error is returned when
   update and Zone sections are not coherent, a NOTAUTH error is
   returned when the DM is not authoritative for the Zone section.  A
   REFUSED error is returned when the DM refuses to proceed to the
   configuration and the requested action.

4.5.3.  Providing information for the Synchronization Channel

   The default IP address used by the HNA for the Synchronization
   Channel is the IP address of the Control Channel.  To provide a
   different IP address, the HNA MAY send a DNS Update message.

   Similarly to the Section 4.5.2, the HNA MAY specify the IP address
   using a DNS update message.  The Zone section sets its ZNAME to the
   parent zone of the Registered Homenet Domain, ZTYPE is set to SOA and
   ZCLASS is set to the zone's type.  Pre-requisite is empty.  The
   Update section is a RRset of type NS.  The Additional Data section
   contains the RRsets of type A or AAAA that designates the IP
   addresses associated to the primary (or the HNA).

   The reason to provide these IP addresses is to keep them unpublished
   and prevent them to be resolved.

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   Upon receiving the DNS update request, the DM reads the IP addresses
   and checks the ZNAME corresponds to the parent zone.  The DM SHOULD
   ignore a non empty Pre-requisite section.  The DM configures the
   secondary with the IP addresses and returns a NOERROR response to
   indicate it is committed to serve as a secondary.

   Similarly to Section 4.5.2, DNS errors are used and an error
   indicates the DM is not configured as a secondary.

4.5.4.  HNA instructing deleting the delegation

   To instruct to delete the delegation the HNA SHOULD send a DNS UPDATE
   Delete message.

   The Zone section sets its ZNAME to the Registered Homenet Domain, the
   ZTYPE to SOA and the ZCLASS to zone's type.  The Pre-requisite
   section is empty.  The Update section is a RRset of type NS with the
   NAME set to the Registered Domain Name.  As indicated by [RFC2136]
   Section 2.5.2 the delete instruction is set by setting the TTL to 0,
   the Class to ANY, the RDLENGTH to 0 and the RDATA MUST be empty.  The
   Additional Data section is empty.

   Upon receiving the DNS update request, the DM checks the request and
   removes the delegation.  The DM returns a NOERROR response to
   indicate the delegation has been deleted.  Similarly to
   Section 4.5.2, DNS errors are used and an error indicates the
   delegation has not been deleted.

4.6.  Securing the Control Channel

   The control channel between the HNA and the DM MUST be secured at
   both the HNA and the DM.

   Secure protocols (like TLS [RFC8446] SHOULD be used to secure the
   transactions between the DM and the HNA.

   The advantage of TLS is that this technology is widely deployed, and
   most of the devices already embed TLS libraries, possibly also taking
   advantage of hardware acceleration.  Further, TLS provides
   authentication facilities and can use certificates to mutually
   authenticate the DM and HNA at the application layer, including
   available API.  On the other hand, using TLS requires implementing
   DNS exchanges over TLS, as well as a new service port.

   The HNA SHOULD authenticate inbound connections from the DM using
   standard mechanisms, such as a public certificate with baked-in root
   certificates on the HNA, or via DANE [RFC6698].  The HNA is expected

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   to be provisioned with a connection to the DM by the manufacturer, or
   during some user-initiated onboarding process, see Section 10.

   The DM SHOULD authenticate the HNA and check that inbound messages
   are from the appropriate client.  The DM MAY use a self-signed CA
   certificate mechanism per HNA, or public certificates for this
   purpose.

   IPsec [RFC4301] and IKEv2 [RFC7296] were considered.  They would need
   to operate in transport mode, and the authenticated end points would
   need to be visible to the applications, and this is not commonly
   available at the time of this writing.

   A pure DNS solution using TSIG and/or SIG(0) to authenticate message
   was also considered.  Section 10 envisions one mechanism would
   involve the end user, with a browser, signing up to a service
   provider, with a resulting OAUTH2 token to be provided to the HNA.  A
   way to translate this OAUTH2 token from HTTPS web space to DNS SIG(0)
   space seems overly problematic, and so the enrollment protocol using
   web APIs was determined to be easier to implement at scale.

   Note also that authentication of message exchanges between the HNA
   and the DM SHOULD NOT use the external IP address of the HNA to index
   the appropriate keys.  As detailed in Section 11, the IP addresses of
   the DM and the hidden primary are subject to change, for example
   while the network is being renumbered.  This means that the necessary
   keys to authenticate transaction SHOULD NOT be indexed using the IP
   address, and SHOULD be resilient to IP address changes.

4.7.  Implementation Concerns

   The Hidden Primary Server on the HNA differs from a regular
   authoritative server for the home network due to:

   Interface Binding:  the Hidden Primary Server will almost certainly
      listen on the WAN Interface, whereas a regular Homenet
      Authoritative Servers would listen on the internal home network
      interface.

   Limited exchanges:  the purpose of the Hidden Primary Server is to
      synchronize with the DM, not to serve any zones to end users, or
      the public Internet.

   As a result, exchanges are performed with specific nodes (the DM).
   Further, exchange types are limited.  The only legitimate exchanges
   are: NOTIFY initiated by the Hidden Primary and IXFR or AXFR
   exchanges initiated by the DM.

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   On the other hand, regular authoritative servers would respond to any
   hosts, and any DNS query would be processed.  The HNA SHOULD filter
   IXFR/AXFR traffic and drop traffic not initiated by the DM.  The HNA
   MUST at least allow SOA lookups of the Homenet Zone.

5.  Synchronization Channel

   The DM Synchronization Channel is used for communication between the
   HNA and the DM for synchronizing the Public Homenet Zone.  Note that
   the Control Channel and the Synchronization Channel are by
   construction different channels even though there they may use the
   same IP address.  In fact the Control Channel is set between the HNA
   working as a client using port number YYYY (a high range port) toward
   a service provided by the DM at port number XX (well known port).

   On the other hand, the Synchronization Channel is set between the DM
   working as a client using port ZZZZ ( a high range port) toward a
   service a service provided by the HNA at port XX.

   As a result, even though the same couple of IP addresses may be
   involved the Control Channel and the Synchronization Channel are
   always distinct channels.

   Uploading and dynamically updating the zone file on the DM can be
   seen as zone provisioning between the HNA (Hidden Primary) and the DM
   (Secondary Server).  This can be handled via AXFR + DNS Update.

   The use of a primary / secondary mechanism is RECOMMENDED instead of
   the use of DNS Update.  The primary / secondary mechanism is
   RECOMMENDED as it scales better and avoids DoS attacks.  Note that
   even when UPDATE messages are used, these messages are using a
   distinct channel as those used to set the configuration.

   Note that there is no standard way to distribute a DNS primary
   between multiple devices.  As a result, if multiple devices are
   candidate for hosting the Hidden Primary, some specific mechanisms
   should be designed so the home network only selects a single HNA for
   the Hidden Primary.  Selection mechanisms based on HNCP [RFC7788] are
   good candidates.

   The HNA acts as a Hidden Primary Server, which is a regular
   authoritative DNS Server listening on the WAN interface.

   The DM is configured as a secondary for the Registered Homenet Domain
   Name.  This secondary configuration has been previously agreed
   between the end user and the provider of the DOI as part of either
   the provisioning or due to receipt of DNS Update messages on the DM
   Control Channel.

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   The Homenet Reverse Zone MAY also be updated either with DNS UPDATE
   [RFC2136] or using a primary / secondary synchronization.

5.1.  Securing the Synchronization Channel

   The Synchronization Channel uses standard DNS requests.

   First the primary notifies the secondary that the zone must be
   updated and eaves the secondary to proceed with the update when
   possible/convenient.

   Then, a NOTIFY message is sent by the primary, which is a small
   packet that is less likely to load the secondary.

   Finally, the AXFR [RFC1034] or IXFR [RFC1995] query performed by the
   secondary is a small packet sent over TCP (Section 4.2 [RFC5936]),
   which mitigates reflection attacks using a forged NOTIFY.

   The AXFR request from the DM to the HNA SHOULD be secured and the use
   of TLS is RECOMMENDED [I-D.ietf-dprive-xfr-over-tls]

   When using TLS, the HNA MAY authenticate inbound connections from the
   DM using standard mechanisms, such as a public certificate with
   baked-in root certificates on the HNA, or via DANE [RFC6698].  In
   addition, to guarantee the DM remains the same across multiple TLS
   session, the HNA and DM MAY implement [RFC8672].

   The HNA SHOULD apply an ACL on inbound AXFR requests to ensure they
   only arrive from the DM Synchronization Channel.  In this case, the
   HNA SHOULD regularly check (via DNS resolution) that the address of
   the DM in the filter is still valid.

6.  DM Distribution Channel

   The DM Distribution Channel is used for communication between the DM
   and the Public Authoritative Servers.  The architecture and
   communication used for the DM Distribution Channels is outside the
   scope of this document, and there are many existing solutions
   available e.g. rsynch, DNS AXFR, REST, DB copy.

7.  HNA Security Policies

   This section details security policies related to the Hidden Primary
   / Secondary synchronization.

   The HNA, as Hidden Primary SHOULD drop any queries from the home
   network.  This could be implemented via port binding and/or firewall
   rules.  The precise mechanism deployed is out of scope of this

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   document.  The Hidden Primary SHOULD drop any DNS queries arriving on
   the WAN interface that are not issued from the DM.  The Hidden
   Primary SHOULD drop any outgoing packets other than DNS NOTIFY query,
   SOA response, IXFR response or AXFR responses.  The Hidden Primary
   SHOULD drop any incoming packets other than DNS NOTIFY response, SOA
   query, IXFR query or AXFR query.  The Hidden Primary SHOULD drop any
   non protected IXFR or AXFR exchange,depending on how the
   synchronization is secured.

8.  DNSSEC compliant Homenet Architecture

   [RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on both
   the authoritative server and the resolver.  The resolver side is out
   of scope of this document, and only the authoritative part of the
   server is considered.

   This document assumes the HNA signs the Public Homenet Zone.

   Secure delegation is achieved only if the DS RRset is properly set in
   the parent zone.  Secure delegation is performed by the HNA or the
   DOIs.

   The DS RRset can be updated manually with nsupdate for example.  This
   requires the HNA or the DOI to be authenticated by the DNS server
   hosting the parent of the Public Homenet Zone.  Such a trust channel
   between the HNA and the parent DNS server may be hard to maintain
   with HNAs, and thus may be easier to establish with the DOI.  In
   fact, the Public Authoritative Server(s) may use Automating DNSSEC
   Delegation Trust Maintenance [RFC7344].

9.  Homenet Reverse Zone Channels Configuration

   The Public Homenet Zone is associated to a Registered Homenet Domain
   and the ownership of that domain requires a specific registration
   from the end user as well as the HNA being provisioned with some
   authentication credentials.  Such steps are mandatory unless the DOI
   has some other means to authenticate the HNA.  Such situation may
   occur, for example, when the ISP provides the Homenet Domain as well
   as the DOI.

   In this case, the HNA may be authenticated by the physical link
   layer, in which case the authentication of the HNA may be performed
   without additional provisioning of the HNA.  While this may not be so
   common for the Public Homenet Zone, this situation is expected to be
   quite common for the Reverse Homenet Zone.

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   More specifically, a common case is that the upstream ISP provides
   the IPv6 prefix to the Homenet with a IA_PD [RFC8415] option and
   manages the DOI of the associated reverse zone.

   This leave place for setting up automatically the relation between
   HNA and the DNS Outsourcing infrastructure as described in
   [I-D.ietf-homenet-naming-architecture-dhc-options].

   In the case of the reverse zone, the DOI authenticates the source of
   the updates by IPv6 Access Control Lists.  In the case of the reverse
   zone, the ISP knows exactly what addresses have been delegated.  The
   HNA SHOULD therefore always originate Synchronization Channel updates
   from an IP address within the zone that is being updated.

   For example, if the ISP has assigned 2001:db8:f00d::/64 to the WAN
   interface (by DHCPv6, or PPP/RA), then the HNA should originate
   Synchronization Channel updates from, for example, 2001:db8:f00d::2.

   An ISP that has delegated 2001:db8:babe::/56 to the HNA via
   DHCPv6-PD, then HNA should originate Synchronization Channel updates
   an IP within that subnet, such as 2001:db8:babe:0001::2.

   With this relation automatically configured, the synchronization
   between the Home network and the DOI happens similarly as for the
   Public Homenet Zone described earlier in this document.

   Note that for home networks connected to by multiple ISPs, each ISP
   provides only the DOI of the reverse zones associated to the
   delegated prefix.  It is also likely that the DNS exchanges will need
   to be performed on dedicated interfaces as to be accepted by the ISP.
   More specifically, the reverse zone associated to prefix 1 will not
   be possible to be performs by the HNA using an IP address that
   belongs to prefix 2.  Such constraints does not raise major concerns
   either for hot standby or load sharing configuration.

   With IPv6, the domain space for IP addresses is so large that reverse
   zone may be confronted with scalability issues.  How the reverse zone
   is generated is out of scope of this document.  [RFC8501] provides
   guidance on how to address scalability issues.

10.  Homenet Public Zone Channel Configurations

   This document does not deal with how the HNA is provisioned with a
   trusted relationship to the Distribution Manager for the forward
   zone.

   This section details what needs to be provisioned into the HNA and
   serves as a requirements statement for mechanisms.

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   The HNA needs to be provisioned with:

   o  the Registered Domain (e.g., myhome.isp.example )

   o  the contact info for the Distribution Manager (DM), including the
      DNS name (FQDN), possibly including the IP literal, and a
      certificate (or anchor) to be used to authenticate the service

   o  the DM transport protocol and port (the default is DNS over TLS,
      on port 853)

   o  the HNA credentials used by the DM for its authentication.

   The HNA will need to select an IP address for communication for the
   Synchronization Channel.  This is typically the WAN address of the RG
   router, but could be an IPv6 LAN address in the case of a home with
   multiple ISPs (and multiple border routers).  This is detailed in
   Section 4.5.3 when the NS and A or AAAA RRsets are communicated.

   The above parameters MUST be be provisioned for ISP-specific reverse
   zones, as per [I-D.ietf-homenet-naming-architecture-dhc-options].
   ISP-specific forward zones MAY also be provisioned using
   [I-D.ietf-homenet-naming-architecture-dhc-options], but zones which
   are not related to a specific ISP zone (such as with a DNS provider)
   must be provisioned through other means.

   Similarly, if the HNA is provided by a registrar, the HNA may be
   handed pre-configured to end user.

   In the absence of specific pre-established relation, these pieces of
   information may be entered manually by the end user.  In order to
   ease the configuration from the end user the following scheme may be
   implemented.

   The HNA may present the end user a web interface where it provides
   the end user the ability to indicate the Registered Homenet Domain or
   the registrar for example a preselected list.  Once the registrar has
   been selected, the HNA redirects the end user to that registrar in
   order to receive a access token.  The access token will enable the
   HNA to retrieve the DM parameters associated to the Registered
   Domain.  These parameters will include the credentials used by the
   HNA to establish the Control and Synchronization Channels.

   Such architecture limits the necessary steps to configure the HNA
   from the end user.

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11.  Renumbering

   This section details how renumbering is handled by the Hidden Primary
   server or the DM.  Both types of renumbering are discussed i.e.
   "make-before-break" and "break-before-make" (aka flash renumbering).

   In the make-before-break renumbering scenario, the new prefix is
   advertised, the network is configured to prepare the transition to
   the new prefix.  During a period of time, the two prefixes old and
   new coexist, before the old prefix is completely removed.

   In the break-before-make renumbering scenario, the new prefix is
   advertised making the old prefix obsolete.

   Renumbering has been extensively described in [RFC4192] and analyzed
   in [RFC7010] and the reader is expected to be familiar with them
   before reading this section.

11.1.  Hidden Primary

   In a renumbering scenario, the HNA or Hidden Primary is informed it
   is being renumbered.  In most cases, this occurs because the whole
   home network is being renumbered.  As a result, the Public Homenet
   Zone will also be updated.  Although the new and old IP addresses may
   be stored in the Public Homenet Zone, we recommend that only the
   newly reachable IP addresses be published.

   To avoid reachability disruption, IP connectivity information
   provided by the DNS SHOULD be coherent with the IP in use.  In our
   case, this means the old IP address SHOULD NOT be provided via the
   DNS when it is not reachable anymore.  Let for example TTL be the TTL
   associated with a RRset of the Public Homenet Zone, it may be cached
   for TTL seconds.  Let T_NEW be the time the new IP address replaces
   the old IP address in the Homenet Zone, and T_OLD_UNREACHABLE the
   time the old IP is not reachable anymore.

   In the case of the make-before-break, seamless reachability is
   provided as long as T_OLD_UNREACHABLE - T_NEW > 2 * TTL.  If this is
   not satisfied, then devices associated with the old IP address in the
   home network may become unreachable for 2 * TTL - (T_OLD_UNREACHABLE
   - T_NEW).  In the case of a break-before-make, T_OLD_UNREACHABLE =
   T_NEW, and the device may become unreachable up to 2 * TTL.  Of
   course if T_NEW >= T_OLD_UNREACHABLE, the disruption is increased.

   Once the Public Homenet Zone file has been updated on the Hidden
   Primary, the Hidden Primary needs to inform the DOI that the Public
   Homenet Zone has been updated and that the IP address to use to
   retrieve the updated zone has also been updated.  Both notifications

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   are performed using regular DNS exchanges.  Mechanisms to update an
   IP address provided by lower layers with protocols like SCTP
   [RFC4960], MOBIKE [RFC4555] are not considered in this document.
   Instead the IP address of the HNA is updated using the
   Synchronization Channel as described in Section 4.3.

12.  Privacy Considerations

   Outsourcing the DNS Authoritative service from the HNA to a third
   party raises a few privacy related concerns.

   The Public Homenet Zone lists the names of services hosted in the
   home network.  Combined with blocking of AXFR queries, the use of
   NSEC3 [RFC5155] (vs NSEC [RFC4034]) prevents an attacker from being
   able to walk the zone, to discover all the names.  However, the
   attacker may be able to walk the reverse DNS zone, or use other
   reconnaissance techniques to learn this information as described in
   [RFC7707].

   In general a home network owner is expected to publish only names for
   which there is some need to be able to reference externally.
   Publication of the name does not imply that the service is
   necessarily reachable from any or all parts of the Internet.
   [RFC7084] mandates that the outgoing-only policy [RFC6092] be
   available, and in many cases it is configured by default.  A well
   designed User Interface would combine a policy for making a service
   public by a name with a policy on who may access it.

   In many cases, the home network owner wishes to publish names for
   services that only they will be able to access.  The access control
   may consist of an IP source address range, or access may be
   restricted via some VPN functionality.  The purpose of publishing the
   name is so that the service may be access by the same name both
   within the home, and outside the home.  Sending traffic to the
   relevant IPv6 address causes the relevant VPN policy to be enacted
   upon.

   While the problem of getting access to internal names has been solved
   in Enterprise configurations with a split-DNS, and such a thing could
   be done in the home, many recent improvements to VPN user interfaces
   make it more likely that an individual might have multiple
   connections configured.  For instance, an adult child checking on the
   state of a home automation system for a parent.

   In addition to the Public Homenet Zone, pervasive DNS monitoring can
   also monitor the traffic associated with the Public Homenet Zone.
   This traffic may provide an indication of the services an end user
   accesses, plus how and when they use these services.  Although,

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   caching may obfuscate this information inside the home network, it is
   likely that outside your home network this information will not be
   cached.

13.  Security Considerations

   This document exposes a mechanism that prevents the HNA from being
   exposed to the Internet and served DNS request from the Internet.
   These requests are instead served by the DOI.  While this limits the
   level of exposure of the HNA, the HNA remains exposed to the Internet
   with communications with the DOI.  This section analyses the attack
   surface associated to these communications.  In addition, the DOI
   exposes data that are related to the home network.  This section also
   analyses the implication of such exposure.

13.1.  HNA DM channels

   The channels between HNA and DM are mutually authenticated and
   encrypted with TLS [RFC8446] and its associated security
   considerations apply.  To ensure the multiple TLS session are are
   continuously authenticating the same entity, TLS may take advantage
   of second factor authentication as described in [RFC8672].

   At the time of writing TLS 1.2 or TLS 1.3 can be used and TLS 1.3 (or
   newer) SHOULD be supported.

   The DNS protocol is subject to reflection attacks, however, these
   attacks are largely applicable when DNS is carried over UDP.  The
   interfaces between the HNA and DM are using TLS over TCP, which
   prevents such reflection attacks.  Note that Public Authoritative
   servers hosted by the DOI are subject to such attacks, but that is
   out of scope of our document.

   Note that in the case of the Reverse Homenet Zone, the data is less
   subject to attacks than in the Public Homenet Zone.  In addition, the
   DM and RDM may be provided by the ISP - as described in
   [I-D.ietf-homenet-naming-architecture-dhc-options], in which case DM
   and RDM might be less exposed to attacks - as communications within a
   network.

13.2.  Names are less secure than IP addresses

   This document describes how an end user can make their services and
   devices from his home network reachable on the Internet by using
   names rather than IP addresses.  This exposes the home network to
   attackers, since names are expected to include less entropy than IP
   addresses.  In fact, with IP addresses, the Interface Identifier is
   64 bits long leading to up to 2^64 possibilities for a given

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   subnetwork.  This is not to mention that the subnet prefix is also of
   64 bits long, thus providing up to 2^64 possibilities.  On the other
   hand, names used either for the home network domain or for the
   devices present less entropy (livebox, router, printer, nicolas,
   jennifer, ...) and thus potentially exposes the devices to dictionary
   attacks.

13.3.  Names are less volatile than IP addresses

   IP addresses may be used to locate a device, a host or a service.
   However, home networks are not expected to be assigned a time
   invariant prefix by ISPs.  As a result, observing IP addresses only
   provides some ephemeral information about who is accessing the
   service.  On the other hand, names are not expected to be as volatile
   as IP addresses.  As a result, logging names over time may be more
   valuable than logging IP addresses, especially to profile an end
   user's characteristics.

   PTR provides a way to bind an IP address to a name.  In that sense,
   responding to PTR DNS queries may affect the end user's privacy.  For
   that reason end users may choose not to respond to PTR DNS queries
   and MAY instead return a NXDOMAIN response.

14.  Information Model for Outsourced information

   This section is non-normative for the front-end protocol.  It
   specifies an optional format for the set of parameters required by
   the HNA to configure the naming architecture of this document.

   In cases where a home router has not been provisioned by the
   manufacturer (when forward zones are provided by the manufacturer),
   or by the ISP (when the ISP provides this service), then a home user/
   owner will need to configure these settings via an administrative
   interface.

   By defining a standard format (in JSON) for this configuration
   information, the user/owner may be able to just copy and paste a
   configuration blob from the service provider into the administrative
   interface of the HNA.

   This format may also provide the basis for a future OAUTH2 [RFC6749]
   flow that could do the setup automatically.

   The HNA needs to be configured with the following parameters as
   described by this CDDL [RFC8610].  These are the parameters are
   necessary to establish a secure channel between the HNA and the DM as
   well as to specify the DNS zone that is in the scope of the
   communication.

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   hna-configuration = {
     "registered_domain" : tstr,
     "dm"                : tstr,
     ? "dm_transport" : "DoT"
     ? "dm_port"        : uint,
     ? "dm_acl"         : hna-acl / [ +hna-acl ]
     ? "hna_auth_method": hna-auth-method
     ? "hna_certificate": tstr
   }

   hna-acl          = tstr
   hna-auth-method  /= "certificate"

   For example:

 {
   "registered_domain" : "n8d234f.r.example.net",
   "dm"                : "2001:db8:1234:111:222::2",
   "dm_transport"      : "DoT",
   "dm_port"           : 4433,
   "dm_acl"            : "2001:db8:1f15:62e:21c::/64"
                    or [ "2001:db8:1f15:62e:21c::/64", ... ]
   "hna_auth_method"   : "certificate",
   "hna_certificate"   : "-----BEGIN CERTIFICATE-----\nMIIDTjCCFGy....",
 }

14.1.  Outsourced Information Model

   Registered Homenet Domain (zone)  The Domain Name of the zone.
      Multiple Registered Homenet Domains may be provided.  This will
      generate the creation of multiple Public Homenet Zones.  This
      parameter is MANDATORY.

   Distribution Manager notification address (dm)  The associated FQDNs
      or IP addresses of the DM to which DNS notifies should be sent.
      This parameter is MANDATORY.  IP addresses are optional and the
      FQDN is sufficient and preferred.  If there are concerns about the
      security of the name to IP translation, then DNSSEC should be
      employed.

   As the session between the HNA and the DM is authenticated with TLS,
   the use of names is easier.

   As certificates are more commonly emitted for FQDN than for IP
   addresses, it is preferred to use names and authenticate the name of
   the DM during the TLS session establishment.

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   Supported Transport (dm_transport)  The transport that carries the
      DNS exchanges between the HNA and the DM.  Typical value is "DoT"
      but it may be extended in the future with "DoH", "DoQ" for
      example.  This parameter is OPTIONAL and by default the HNA uses
      DoT.

   Distribution Manager Port (dm_port)  Indicates the port used by the
      DM.  This parameter is OPTIONAL and the default value is provided
      by the Supported Transport.  In the future, additional transport
      may not have default port, in which case either a default port
      needs to be defined or this parameter become MANDATORY.

   Note that HNA does not defines ports for the Synchronization Channel.
   In any case, this is not expected to part of the configuration, but
   instead negotiated through the Configuration Channel.  Currently the
   Configuration Channel does not provide this, and limits its agility
   to a dedicated IP address.  If such agility is needed in the future,
   additional exchanges will need to be defined.

   Authentication Method ("hna_auth_method"):  How the HNA authenticates
      itself to the DM within the TLS connection(s).  The authentication
      meth of can typically be "certificate", "psk" or "none".  This
      Parameter is OPTIONAL and by default the Authentication Method is
      "certificate".

   Authentication data ("hna_certificate", "hna_key"): : The certificate
   chain used to authenticate the HNA.  This parameter is OPTIONAL and
   when not specified, a self-signed certificate is used.

   Distribution Manager AXFR permission netmask (dm_acl):  The subnet
      from which the CPE should accept SOA queries and AXFR requests.  A
      subnet is used in the case where the DNS Outsourced Infrastructure
      consists of a number of different systems.  An array of addresses
      is permitted.  This parameter is OPTIONAL and if unspecified, the
      CPE the IP addresses specified in the dm_notify parameters or the
      IP addresses that result from the DNS(SEC) resolution when
      dm_notify specifies a FQDN.

   For forward zones, the relationship between the HNA and the forward
   zone provider may be the result of a number of transactions:

   1.  The forward zone outsourcing may be provided by the maker of the
       Homenet router.  In this case, the identity and authorization
       could be built in the device at manufacturer provisioning time.
       The device would need to be provisioned with a device-unique
       credential, and it is likely that the Registered Homenet Domain
       would be derived from a public attribute of the device, such as a

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       serial number (see Appendix B or
       [I-D.richardson-homerouter-provisioning] for more details ).

   2.  The forward zone outsourcing may be provided by the Internet
       Service Provider.  In this case, the use of
       [I-D.ietf-homenet-naming-architecture-dhc-options] to provide the
       credentials is appropriate.

   3.  The forward zone may be outsourced to a third party, such as a
       domain registrar.  In this case, the use of the JSON-serialized
       YANG data model described in this section is appropriate, as it
       can easily be copy and pasted by the user, or downloaded as part
       of a web transaction.

   For reverse zones, the relationship is always with the upstream ISP
   (although there may be more than one), and so
   [I-D.ietf-homenet-naming-architecture-dhc-options] is always the
   appropriate interface.

   The following is an abbridged example of a set of data that
   represents the needed configuration parameters for outsourcing.

15.  IANA Considerations

   This document has no actions for IANA.

16.  Acknowledgment

   The authors wish to thank Philippe Lemordant for its contributions on
   the early versions of the draft; Ole Troan for pointing out issues
   with the IPv6 routed home concept and placing the scope of this
   document in a wider picture; Mark Townsley for encouragement and
   injecting a healthy debate on the merits of the idea; Ulrik de Bie
   for providing alternative solutions; Paul Mockapetris, Christian
   Jacquenet, Francis Dupont and Ludovic Eschard for their remarks on
   HNA and low power devices; Olafur Gudmundsson for clarifying DNSSEC
   capabilities of small devices; Simon Kelley for its feedback as
   dnsmasq implementer; Andrew Sullivan, Mark Andrew, Ted Lemon, Mikael
   Abrahamson, and Ray Bellis for their feedback on handling different
   views as well as clarifying the impact of outsourcing the zone
   signing operation outside the HNA; Mark Andrew and Peter Koch for
   clarifying the renumbering.

17.  Contributors

   The co-authors would like to thank Chris Griffiths and Wouter
   Cloetens that provided a significant contribution in the early
   versions of the document.

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18.  References

18.1.  Normative References

   [I-D.ietf-dprive-xfr-over-tls]
              Toorop, W., Dickinson, S., Sahib, S., Aras, P., and A.
              Mankin, "DNS Zone Transfer-over-TLS", draft-ietf-dprive-
              xfr-over-tls-11 (work in progress), April 2021.

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC1995]  Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995,
              DOI 10.17487/RFC1995, August 1996,
              <https://www.rfc-editor.org/info/rfc1995>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2136]  Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound,
              "Dynamic Updates in the Domain Name System (DNS UPDATE)",
              RFC 2136, DOI 10.17487/RFC2136, April 1997,
              <https://www.rfc-editor.org/info/rfc2136>.

   [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Resource Records for the DNS Security Extensions",
              RFC 4034, DOI 10.17487/RFC4034, March 2005,
              <https://www.rfc-editor.org/info/rfc4034>.

   [RFC4192]  Baker, F., Lear, E., and R. Droms, "Procedures for
              Renumbering an IPv6 Network without a Flag Day", RFC 4192,
              DOI 10.17487/RFC4192, September 2005,
              <https://www.rfc-editor.org/info/rfc4192>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

   [RFC4555]  Eronen, P., "IKEv2 Mobility and Multihoming Protocol
              (MOBIKE)", RFC 4555, DOI 10.17487/RFC4555, June 2006,
              <https://www.rfc-editor.org/info/rfc4555>.

   [RFC4960]  Stewart, R., Ed., "Stream Control Transmission Protocol",
              RFC 4960, DOI 10.17487/RFC4960, September 2007,
              <https://www.rfc-editor.org/info/rfc4960>.

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   [RFC5155]  Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
              Security (DNSSEC) Hashed Authenticated Denial of
              Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008,
              <https://www.rfc-editor.org/info/rfc5155>.

   [RFC5936]  Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol
              (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010,
              <https://www.rfc-editor.org/info/rfc5936>.

   [RFC6092]  Woodyatt, J., Ed., "Recommended Simple Security
              Capabilities in Customer Premises Equipment (CPE) for
              Providing Residential IPv6 Internet Service", RFC 6092,
              DOI 10.17487/RFC6092, January 2011,
              <https://www.rfc-editor.org/info/rfc6092>.

   [RFC6644]  Evans, D., Droms, R., and S. Jiang, "Rebind Capability in
              DHCPv6 Reconfigure Messages", RFC 6644,
              DOI 10.17487/RFC6644, July 2012,
              <https://www.rfc-editor.org/info/rfc6644>.

   [RFC6698]  Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
              of Named Entities (DANE) Transport Layer Security (TLS)
              Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
              2012, <https://www.rfc-editor.org/info/rfc6698>.

   [RFC6762]  Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
              DOI 10.17487/RFC6762, February 2013,
              <https://www.rfc-editor.org/info/rfc6762>.

   [RFC6763]  Cheshire, S. and M. Krochmal, "DNS-Based Service
              Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
              <https://www.rfc-editor.org/info/rfc6763>.

   [RFC6887]  Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and
              P. Selkirk, "Port Control Protocol (PCP)", RFC 6887,
              DOI 10.17487/RFC6887, April 2013,
              <https://www.rfc-editor.org/info/rfc6887>.

   [RFC7010]  Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W.
              George, "IPv6 Site Renumbering Gap Analysis", RFC 7010,
              DOI 10.17487/RFC7010, September 2013,
              <https://www.rfc-editor.org/info/rfc7010>.

   [RFC7084]  Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic
              Requirements for IPv6 Customer Edge Routers", RFC 7084,
              DOI 10.17487/RFC7084, November 2013,
              <https://www.rfc-editor.org/info/rfc7084>.

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   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
              2014, <https://www.rfc-editor.org/info/rfc7296>.

   [RFC7344]  Kumari, W., Gudmundsson, O., and G. Barwood, "Automating
              DNSSEC Delegation Trust Maintenance", RFC 7344,
              DOI 10.17487/RFC7344, September 2014,
              <https://www.rfc-editor.org/info/rfc7344>.

   [RFC7368]  Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J.
              Weil, "IPv6 Home Networking Architecture Principles",
              RFC 7368, DOI 10.17487/RFC7368, October 2014,
              <https://www.rfc-editor.org/info/rfc7368>.

   [RFC7558]  Lynn, K., Cheshire, S., Blanchet, M., and D. Migault,
              "Requirements for Scalable DNS-Based Service Discovery
              (DNS-SD) / Multicast DNS (mDNS) Extensions", RFC 7558,
              DOI 10.17487/RFC7558, July 2015,
              <https://www.rfc-editor.org/info/rfc7558>.

   [RFC7707]  Gont, F. and T. Chown, "Network Reconnaissance in IPv6
              Networks", RFC 7707, DOI 10.17487/RFC7707, March 2016,
              <https://www.rfc-editor.org/info/rfc7707>.

   [RFC7788]  Stenberg, M., Barth, S., and P. Pfister, "Home Networking
              Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
              2016, <https://www.rfc-editor.org/info/rfc7788>.

   [RFC7858]  Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
              and P. Hoffman, "Specification for DNS over Transport
              Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
              2016, <https://www.rfc-editor.org/info/rfc7858>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8375]  Pfister, P. and T. Lemon, "Special-Use Domain
              'home.arpa.'", RFC 8375, DOI 10.17487/RFC8375, May 2018,
              <https://www.rfc-editor.org/info/rfc8375>.

   [RFC8415]  Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A.,
              Richardson, M., Jiang, S., Lemon, T., and T. Winters,
              "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
              RFC 8415, DOI 10.17487/RFC8415, November 2018,
              <https://www.rfc-editor.org/info/rfc8415>.

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   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8555]  Barnes, R., Hoffman-Andrews, J., McCarney, D., and J.
              Kasten, "Automatic Certificate Management Environment
              (ACME)", RFC 8555, DOI 10.17487/RFC8555, March 2019,
              <https://www.rfc-editor.org/info/rfc8555>.

18.2.  Informative References

   [I-D.ietf-dprive-dnsoquic]
              Huitema, C., Mankin, A., and S. Dickinson, "Specification
              of DNS over Dedicated QUIC Connections", draft-ietf-
              dprive-dnsoquic-02 (work in progress), February 2021.

   [I-D.ietf-homenet-naming-architecture-dhc-options]
              Migault, D., Weber, R., and T. Mrugalski, "DHCPv6 Options
              for Home Network Naming Authority", draft-ietf-homenet-
              naming-architecture-dhc-options-12 (work in progress),
              April 2021.

   [I-D.ietf-homenet-simple-naming]
              Lemon, T., Migault, D., and S. Cheshire, "Homenet Naming
              and Service Discovery Architecture", draft-ietf-homenet-
              simple-naming-03 (work in progress), October 2018.

   [I-D.richardson-homerouter-provisioning]
              Richardson, M., "Provisioning Initial Device Identifiers
              into Home Routers", draft-richardson-homerouter-
              provisioning-00 (work in progress), November 2020.

   [RFC2845]  Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.
              Wellington, "Secret Key Transaction Authentication for DNS
              (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000,
              <https://www.rfc-editor.org/info/rfc2845>.

   [RFC2931]  Eastlake 3rd, D., "DNS Request and Transaction Signatures
              ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September
              2000, <https://www.rfc-editor.org/info/rfc2931>.

   [RFC6749]  Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
              RFC 6749, DOI 10.17487/RFC6749, October 2012,
              <https://www.rfc-editor.org/info/rfc6749>.

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   [RFC8094]  Reddy, T., Wing, D., and P. Patil, "DNS over Datagram
              Transport Layer Security (DTLS)", RFC 8094,
              DOI 10.17487/RFC8094, February 2017,
              <https://www.rfc-editor.org/info/rfc8094>.

   [RFC8484]  Hoffman, P. and P. McManus, "DNS Queries over HTTPS
              (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
              <https://www.rfc-editor.org/info/rfc8484>.

   [RFC8499]  Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
              Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
              January 2019, <https://www.rfc-editor.org/info/rfc8499>.

   [RFC8501]  Howard, L., "Reverse DNS in IPv6 for Internet Service
              Providers", RFC 8501, DOI 10.17487/RFC8501, November 2018,
              <https://www.rfc-editor.org/info/rfc8501>.

   [RFC8610]  Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
              Definition Language (CDDL): A Notational Convention to
              Express Concise Binary Object Representation (CBOR) and
              JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
              June 2019, <https://www.rfc-editor.org/info/rfc8610>.

   [RFC8672]  Sheffer, Y. and D. Migault, "TLS Server Identity Pinning
              with Tickets", RFC 8672, DOI 10.17487/RFC8672, October
              2019, <https://www.rfc-editor.org/info/rfc8672>.

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Appendix A.  Envisioned deployment scenarios

   A number of deployment have been envisioned, this section aims at
   providing a brief description.  The use cases are not limitations and
   this section is not normative.

A.1.  CPE Vendor

   A specific vendor with specific relations with a registrar or a
   registry may sell a CPE that is provisioned with provisioned domain
   name.  Such domain name does not need to be necessary human readable.

   One possible way is that the vendor also provisions the HNA with a
   private and public keys as well as a certificate.  Note that these
   keys are not expected to be used for DNSSEC signing.  Instead these
   keys are solely used by the HNA to proceed to the authentication.
   Normally the keys should be necessary and sufficient to proceed to
   the authentication.  The reason to combine the domain name and the
   key is that DOI are likely handle names better than keys and that
   domain names might be used as a login which enables the key to be
   regenerated.

   When the home network owner plugs the CPE at home, the relation
   between HNA and DM is expected to work out-of-the-box.

A.2.  Agnostic CPE

   An CPE that is not preconfigured may also take advantage to the
   protocol defined in this document but some configuration steps will
   be needed.

   1.  The owner of the home network buys a domain name to a registrar,
       and as such creates an account on that registrar

   2.  Either the registrar is also providing the outsourcing
       infrastructure or the home network needs to create a specific
       account on the outsourcing infrastructure.  * If the DOI is the
       registrar, it has by design a proof of ownership of the domain
       name by the homenet owner.  In this case, it is expected the DOI
       provides the necessary parameters to the home network owner to
       configure the HNA.  A good way to provide the parameters would be
       the home network be able to copy/paste a JSON object - see
       Section 14.  What matters at that point is the DOI being able to
       generate authentication credentials for the HNA to authenticate
       itself to the DOI.  This obviously requires the home network to
       provide the public key generated by the HNA in a CSR.

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   o  If the DOI is not the registrar, then the proof of ownership needs
      to be established using protocols like ACME [RFC8555] for example
      that will end in the generation of a certificate.  ACME is used
      here to the purpose of automating the generation of the
      certificate, the CA may be a specific CA or the DOI.  With that
      being done, the DOI has a roof of ownership and can proceed as
      above.

Appendix B.  Example: A manufacturer provisioned HNA product flow

   This scenario is one where a homenet router device manufacturer
   decides to offer DNS hosting as a value add.

   [I-D.richardson-homerouter-provisioning] describes a process for a
   home router credential provisioning system.  The outline of it is
   that near the end of the manufacturing process, as part of the
   firmware loading, the manufacturer provisions a private key and
   certificate into the device.

   In addition to having a assymmetric credential known to the
   manufacturer, the device also has been provisioned with an agreed
   upon name.  In the example in the above document, the name
   "n8d234f.r.example.net" has already been allocated and confirmed with
   the manufacturer.

   The HNA can use the above domain for itself.  It is not very pretty
   or personal, but if the owner wishes a better name, they can arrange
   for it.

   The configuration would look like:

   {
     "dm_notify" : "2001:db8:1234:111:222::2",
     "dm_acl"    : "2001:db8:1234:111:222::/64",
     "dm_ctrl"   : "manufacturer.example.net",
     "dm_port"   : "4433",
     "ns_list"   : [ "ns1.publicdns.example", "ns2.publicdns.example"],
     "zone"      : "n8d234f.r.example.net",
     "auth_method" : "certificate",
     "hna_certificate":"-----BEGIN CERTIFICATE-----\nMIIDTjCCFGy....",
   }

   The dm_ctrl and dm_port values would be built into the firmware.

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Authors' Addresses

   Daniel Migault
   Ericsson
   8275 Trans Canada Route
   Saint Laurent, QC  4S 0B6
   Canada

   EMail: daniel.migault@ericsson.com

   Ralf Weber
   Nominum
   2000 Seaport Blvd
   Redwood City  94063
   US

   EMail: ralf.weber@nominum.com

   Michael Richardson
   Sandelman Software Works
   470 Dawson Avenue
   Ottawa, ON  K1Z 5V7
   Canada

   EMail: mcr+ietf@sandelman.ca

   Ray Hunter
   Globis Consulting BV
   Weegschaalstraat 3
   Eindhoven  5632CW
   NL

   EMail: v6ops@globis.net

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