Internet Engineering Task Force (IETF) D. Migault

Internet Engineering Task Force (IETF) D. Migault
Request for Comments: 9527 Ericsson
Category: Standards Track R. Weber
ISSN: 2070-1721 Akamai
T. Mrugalski
ISC
January 2024

DHCPv6 Options for the Homenet Naming Authority

Abstract

This document defines DHCPv6 options so that a Homenet Naming
Authority (HNA) can automatically set the appropriate configuration
and outsource the authoritative naming service for the home network.
In most cases, the outsourcing mechanism is transparent for the end
user.

Status of This Memo

This is an Internet Standards Track document.

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). Further information on
Internet Standards is available in Section 2 of RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9527.

Copyright Notice

Copyright (c) 2024 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
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Trust Legal Provisions and are provided without warranty as described
in the Revised BSD License.

Table of Contents

1. Introduction
2. Terminology
3. Procedure Overview
4. DHCPv6 Options
4.1. Registered Homenet Domain Option
4.2. Forward Distribution Manager Option
4.3. Reverse Distribution Manager Server Option
4.4. Supported Transport
5. DHCPv6 Behavior
5.1. DHCPv6 Server Behavior
5.2. DHCPv6 Client Behavior
5.3. DHCPv6 Relay Agent Behavior
6. IANA Considerations
6.1. DHCPv6 Option Codes
6.2. Supported Transport Parameter
7. Security Considerations
8. References
8.1. Normative References
8.2. Informative References
Appendix A. Scenarios and Impact on the End User
A.1. Base Scenario
A.2. Third-Party Registered Homenet Domain
A.3. Third-Party DNS Infrastructure
A.4. Multiple ISPs
Acknowledgments
Contributors
Authors' Addresses

1. Introduction

[RFC9526] specifies how an entity designated as the Homenet Naming
Authority (HNA) outsources a Public Homenet Zone to a DNS Outsourcing
Infrastructure (DOI).

This document describes how a network can provision the HNA with a
specific DOI. This could be particularly useful for a DOI partly
managed by an ISP or to make home networks resilient to HNA
replacement. The ISP delegates an IP prefix and the associated
reverse zone to the home network. The ISP is thus aware of the owner
of that IP prefix and, as such, becomes a natural candidate for
hosting the Homenet Reverse Zone -- that is, the Reverse Distribution
Manager (RDM) and potentially the Reverse Public Authoritative
Servers.

In addition, ISPs often identify the line of the home network with a
name. Such name is used for their internal network management
operations and is not a name the home network owner has registered
to. ISPs may leverage such infrastructure and provide the home
network with a specific domain name designated per a Registered
Homenet Domain [RFC9526]. Similarly to the reverse zone, ISPs are
aware of who owns that domain name and may become a natural candidate
for hosting the Homenet Zone -- that is, the Distribution Manager
(DM) and the Public Authoritative Servers.

This document describes DHCPv6 options that enable an ISP to provide
the necessary parameters to the HNA to proceed. More specifically,
the ISP provides the Registered Homenet Domain and the necessary
information on the DM and the RDM so the HNA can manage and upload
the Public Homenet Zone and the Reverse Public Homenet Zone as
described in [RFC9526].

The use of DHCPv6 options may make the configuration completely
transparent to the end user and provides a similar level of trust as
the one used to provide the IP prefix, when provisioned via DHCP.

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.

The reader should be familiar with [RFC9526].

3. Procedure Overview

This section illustrates how an HNA receives the necessary
information via DHCPv6 options to outsource its authoritative naming
service to the DOI. For the sake of simplicity, and similarly to
[RFC9526], this section assumes that the HNA and the home network
DHCPv6 client are colocated on the Customer Premises Equipment (CPE)
router [RFC7368]. Also, note that this is not mandatory, and the
DHCPv6 client may remotely instruct the HNA with a protocol that will
be standardized in the future. In addition, this section assumes
that the responsible entity for the DHCPv6 server is provisioned with
the DM and RDM information, which is associated with the requested
Registered Homenet Domain. This means a Registered Homenet Domain
can be associated with the DHCPv6 client.

This scenario is believed to be the most popular scenario. This
document does not ignore scenarios where the DHCPv6 server does not
have privileged relations with the DM or RDM. These cases are
discussed in Appendix A. Such scenarios do not necessarily require
configuration for the end user and can also be zero configuration.

The scenario considered in this section is as follows:

1. The HNA is willing to outsource the Public Homenet Zone or
Homenet Reverse Zone. The DHCPv6 client is configured to include
in its Option Request Option (ORO) the Registered Homenet Domain
Option (OPTION_REGISTERED_DOMAIN), the Forward Distribution
Manager Option (OPTION_FORWARD_DIST_MANAGER), and the Reverse
Distribution Manager Option (OPTION_REVERSE_DIST_MANAGER) option
codes.

2. The DHCPv6 server responds to the DHCPv6 client with the
requested DHCPv6 options based on the identified homenet. The
DHCPv6 client passes the information to the HNA.

3. The HNA is authenticated (see "Securing the Control Channel"
(Section 6.6) of [RFC9526]) by the DM and the RDM. The HNA
builds the Homenet Zone (or the Homenet Reverse Zone) and
proceeds as described in [RFC9526]. The DHCPv6 options provide
the necessary non-optional parameters described in Appendix B of
[RFC9526]. The HNA may complement the configurations with
additional parameters via means not yet defined. Appendix B of
[RFC9526] describes such parameters that may take some specific
non-default value.

4. DHCPv6 Options

This section details the payload of the DHCPv6 options following the
guidelines of [RFC7227].

4.1. Registered Homenet Domain Option

The Registered Domain Option (OPTION_REGISTERED_DOMAIN) indicates the
fully qualified domain name (FQDN) associated with the home network.

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_REGISTERED_DOMAIN | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
/ Registered Homenet Domain /
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 1: Registered Domain Option

option-code (16 bits): OPTION_REGISTERED_DOMAIN; the option code for
the Registered Homenet Domain (145).

option-len (16 bits): Length in octets of the Registered Homenet
Domain field as described in [RFC8415].

Registered Homenet Domain (variable): The FQDN registered for the
homenet encoded as described in Section 10 of [RFC8415].

4.2. Forward Distribution Manager Option

The Forward Distribution Manager Option (OPTION_FORWARD_DIST_MANAGER)
provides the HNA with the FQDN of the DM as well as the transport
protocols for the communication between the HNA and the DM. As
opposed to IP addresses, the FQDN requires a DNS resolution before
establishing the communication between the HNA and the DM. However,
the use of an FQDN provides multiple advantages over IP addresses.
Firstly, it makes the DHCPv6 option easier to parse and smaller,
especially when IPv4 and IPv6 addresses are expected to be provided.
Then, the FQDN can reasonably be seen as a more stable identifier
than IP addresses as well as a pointer to additional information that
may be useful, in the future, to establish the communication between
the HNA and the DM.

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_FORWARD_DIST_MANAGER | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Supported Transport | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
/ Distribution Manager FQDN /
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 2: Forward Distribution Manager Option

option-code (16 bits): OPTION_FORWARD_DIST_MANAGER; the option code
for the Forward Distribution Manager Option (146).

option-len (16 bits): Length in octets of the enclosed data as
described in [RFC8415].

Supported Transport (16 bits): Defines the Supported Transport by
the DM (see Section 4.4). Each bit represents a supported
transport, and a DM MAY indicate the support of multiple modes.
The bit for DNS over mutually authenticated TLS (DomTLS) MUST be
set.

Distribution Manager FQDN (variable): The FQDN of the DM encoded as
described in Section 10 of [RFC8415].

It is worth noting that the DHCPv6 option specifies the Supported
Transport without specifying any explicit port. Unless the HNA and
the DM have agreed on using a specific port -- for example, by
configuration, or any out-of-band mechanism -- the default port is
used and must be specified. The specification of such default port
may be defined in the specification of the designated Supported
Transport or in any other document. In the case of DomTLS, the
default port value is 853 per DNS over TLS [RFC7858] and DNS Zone
Transfer over TLS [RFC9103].

The need to associate the port value to each Supported Transport in
the DHCPv6 option has been balanced with the difficulty of handling a
list of tuples (transport, port) and the possibility of using a
dedicated IP address for the DM in case the default port is already
in use.

4.3. Reverse Distribution Manager Server Option

The Reverse Distribution Manager Option (OPTION_REVERSE_DIST_MANAGER)
provides the HNA with the FQDN of the DM as well as the transport
protocols for the communication between the HNA and the DM.

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_REVERSE_DIST_MANAGER | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Supported Transport | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
/ Reverse Distribution Manager FQDN /
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 3: Reverse Distribution Manager Option

option-code (16 bits): OPTION_REVERSE_DIST_MANAGER; the option code
for the Reverse Distribution Manager Option (147).

option-len (16 bits): Length in octets of the option-data field as
described in [RFC8415].

Supported Transport (16 bits): Defines the Supported Transport by
the RDM (see Section 4.4). Each bit represents a supported
transport, and an RDM MAY indicate the support of multiple modes.
The bit for DomTLS [RFC7858] MUST be set.

Reverse Distribution Manager FQDN (variable): The FQDN of the RDM
encoded as described in Section 10 of [RFC8415].

For the port number associated to the Supported Transport, the same
considerations as described in Section 4.2 apply.

4.4. Supported Transport

The Supported Transport field of the DHCPv6 option indicates the
Supported Transport protocols. Each bit represents a specific
transport mechanism. A bit set to 1 indicates the associated
transport protocol is supported. The corresponding bits are assigned
as described in Table 2.

DNS over mutually authenticated TLS (DomTLS): Indicates the support
of DNS over TLS [RFC7858] and DNS Zone Transfer over TLS [RFC9103]
as described in [RFC9526].

As an example, the Supported Transport field expressing support for
DomTLS looks as follows and has a numeric value of 0x0001:

0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| must be zero |1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

5. DHCPv6 Behavior

5.1. DHCPv6 Server Behavior

Section 18.3 of [RFC8415] governs server operation regarding option
assignment. As a convenience to the reader, we mention here that the
server will send option foo only if configured with specific values
for foo and if the client requested it. In particular, when
configured, the DHCPv6 server sends the Registered Homenet Domain
Option, Distribution Manager Option, and Reverse Distribution Manager
Option when requested by the DHCPv6 client by including necessary
option codes in its ORO.

5.2. DHCPv6 Client Behavior

The DHCPv6 client includes the Registered Homenet Domain Option,
Distribution Manager Option, and Reverse Distribution Manager Option
in an ORO as specified in Sections 18.2 and 21.7 of [RFC8415].

Upon receiving a DHCPv6 option, as described in this document, in the
Reply message, the HNA SHOULD proceed as described in [RFC9526].

5.3. DHCPv6 Relay Agent Behavior

There are no additional requirements for the DHCPv6 Relay agents.

6. IANA Considerations

6.1. DHCPv6 Option Codes

IANA has assigned the following new DHCPv6 Option Codes in the
"Option Codes" registry maintained at
<https://www.iana.org/assignments/dhcpv6-parameters>.

+=====+=============================+======+===========+===========+
|Value| Description |Client| Singleton | Reference |
| | |ORO | Option | |
+=====+=============================+======+===========+===========+
|145 | OPTION_REGISTERED_DOMAIN |Yes | No | RFC 9527, |
| | | | | Section |
| | | | | 4.1 |
+-----+-----------------------------+------+-----------+-----------+
|146 | OPTION_FORWARD_DIST_MANAGER |Yes | Yes | RFC 9527, |
| | | | | Section |
| | | | | 4.2 |
+-----+-----------------------------+------+-----------+-----------+
|147 | OPTION_REVERSE_DIST_MANAGER |Yes | Yes | RFC 9527, |
| | | | | Section |
| | | | | 4.3 |
+-----+-----------------------------+------+-----------+-----------+

Table 1: Option Codes Registry

6.2. Supported Transport Parameter

IANA has created and maintains a new registry called "Supported
Transport" under the "Dynamic Host Configuration Protocol for IPv6
(DHCPv6)" registry at <https://www.iana.org/assignments/
dhcpv6-parameters>. This registry contains Supported Transport
parameters in the Distributed Manager Option
(OPTION_FORWARD_DIST_MANAGER) or the Reverse Distribution Manager
Option (OPTION_REVERSE_DIST_MANAGER). The different parameters are
defined in Table 2 (Section 6.2).

The Supported Transport field of the DHCPv6 option is a two-octet
field that indicates the Supported Transport protocols. Each bit
represents a specific transport mechanism.

New entries MUST specify the bit position, the transport protocol
description, a mnemonic, and a reference as shown in Table 2.

Changes to the format or policies of the registry are managed by the
IETF via the IESG.

Future code points are assigned under RFC Required per [RFC8126].
The initial registry is as specified in Table 2 below.

+======================+====================+==========+===========+
| Bit Position (least | Transport Protocol | Mnemonic | Reference |
| to most significant) | Description | | |
+======================+====================+==========+===========+
| 0 | DNS over mutually | DomTLS | RFC 9527 |
| | authenticated TLS | | |
+----------------------+--------------------+----------+-----------+
| 1-15 | Unassigned | | |
+----------------------+--------------------+----------+-----------+

Table 2: Supported Transport Registry

7. Security Considerations

The security considerations in [RFC8415] are to be considered. The
trust associated with the information carried by the DHCPv6 options
described in this document is similar to the one associated with the
IP prefix, when configured via DHCPv6.

In some cases, the ISP MAY identify the HNA by its wire line (i.e.,
physically), which may not require relying on TLS to authenticate the
HNA. As the use of TLS is mandatory, it is expected that the HNA
will be provisioned with a certificate. In some cases, the HNA may
use a self-signed certificate.

8. References

8.1. Normative References

[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>.

[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>.

[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.

[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>.

[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>.

[RFC9103] Toorop, W., Dickinson, S., Sahib, S., Aras, P., and A.
Mankin, "DNS Zone Transfer over TLS", RFC 9103,
DOI 10.17487/RFC9103, August 2021,
<https://www.rfc-editor.org/info/rfc9103>.

[RFC9526] Migault, D., Weber, R., Richardson, M., and R. Hunter,
"Simple Provisioning of Public Names for Residential
Networks", RFC 9526, DOI 10.17487/RFC9526, January 2024,
<https://www.rfc-editor.org/info/rfc9526>.

8.2. Informative References

[CNAME-PLUS-DNAME]
Surý, O., "CNAME+DNAME Name Redirection", Work in
Progress, Internet-Draft, draft-sury-dnsop-cname-plus-
dname-01, 15 July 2018,
<https://datatracker.ietf.org/doc/html/draft-sury-dnsop-
cname-plus-dname-01>.

[PD-REVERSE]
Andrews, M., "Automated Delegation of IP6.ARPA reverse
zones with Prefix Delegation", Work in Progress, Internet-
Draft, draft-andrews-dnsop-pd-reverse-02, 5 November 2013,
<https://datatracker.ietf.org/doc/html/draft-andrews-
dnsop-pd-reverse-02>.

[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>.

[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS
Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997,
<https://www.rfc-editor.org/info/rfc2181>.

[RFC6672] Rose, S. and W. Wijngaards, "DNAME Redirection in the
DNS", RFC 6672, DOI 10.17487/RFC6672, June 2012,
<https://www.rfc-editor.org/info/rfc6672>.

[RFC7227] Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
BCP 187, RFC 7227, DOI 10.17487/RFC7227, May 2014,
<https://www.rfc-editor.org/info/rfc7227>.

[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>.

Appendix A. Scenarios and Impact on the End User

This appendix details various scenarios and discusses their impact on
the end user. This appendix is not normative and limits the
description of a limited scope of scenarios that are assumed to be
representative. Many other scenarios may be derived from these.

A.1. Base Scenario

The base scenario, as described in Section 3, is one in which an ISP
manages the DHCPv6 server, DM, and RDM.

The end user subscribes to the ISP (foo), and at subscription time,
it registers foo.example as its Registered Homenet Domain.

In this scenario, the DHCPv6 server, DM, and RDM are managed by the
ISP, so the DHCPv6 server and such can provide authentication
credentials of the HNA to enable secure authenticated transaction
with the DM and the Reverse DM.

The main advantage of this scenario is that the naming architecture
is configured automatically and transparently for the end user. The
drawbacks are that the end user uses a Registered Homenet Domain
managed by the ISP and that it relies on the ISP naming
infrastructure.

A.2. Third-Party Registered Homenet Domain

This appendix considers the case where the end user wants its home
network to use example.com but does not want it to be managed by the
ISP (foo) as a Registered Homenet Domain, and the ISP manages the
home network and still provides foo.example as a Registered Homenet
Domain.

When the end user buys the domain name example.com, it may request to
redirect example.com to foo.example using static redirection with
CNAME [RFC1034] [RFC2181], DNAME [RFC6672], or CNAME+DNAME
[CNAME-PLUS-DNAME]. The only information the end user needs to know
is the domain name assigned by the ISP. Once the redirection has
been configured, the HNA may be changed, and the zone can be updated
as described in Appendix A.1 without any additional configuration
from the end user.

The main advantage of this scenario is that the end user benefits
from the zero configuration of the base scenario in Appendix A.1.
Then, the end user is able to register an unlimited number of domain
names provided by an unlimited number of different third-party
providers for its home network. The drawback of this scenario may be
that the end user still needs to rely on the ISP naming
infrastructure. Note that this may be inconvenient in the case where
the DNS servers provided by the ISPs result in high latency.

A.3. Third-Party DNS Infrastructure

This scenario involves the end user using example.com as a Registered
Homenet Domain and not relying on the authoritative servers provided
by the ISP.

In this appendix, we limit the outsourcing of the DM and Public
Authoritative Server(s) to a third party. The Reverse Public
Authoritative Server(s) and the RDM remain managed by the ISP as the
IP prefix is managed by the ISP.

Outsourcing to a third-party DM can be performed in the following
ways:

1. Updating the DHCPv6 server information. One can imagine a GUI
interface that enables the end user to modify its profile
parameters. Again, this configuration update only needs to be
performed one time.

2. Uploading the configuration of the DM to the HNA. In some cases,
the provider of the CPE router hosting the HNA may be the
registrar, and the registrar may provide the CPE router already
configured. In other cases, the CPE router may request the end
user to log into the registrar to validate the ownership of the
Registered Homenet Domain and agree on the necessary credentials
to secure the communication between the HNA and the DM. As
described in [RFC9526], such settings could be performed in an
almost automatic way as to limit the necessary interactions with
the end user.

A.4. Multiple ISPs

This scenario involves an HNA connected to multiple ISPs.

Suppose the HNA has configured each of its interfaces independently
with each ISP as described in Appendix A.1. Each ISP provides a
different Registered Homenet Domain.

The protocol and DHCPv6 options described in this document are fully
compatible with an HNA connected to multiple ISPs with multiple
Registered Homenet Domains. However, the HNA should be able to
handle different Registered Homenet Domains. This is an
implementation issue, which is outside the scope of this document.

If an HNA is not able to handle multiple Registered Homenet Domains,
the HNA may remain connected to multiple ISPs with a single
Registered Homenet Domain. In this case, one entity is chosen to
host the Registered Homenet Domain. This entity may be an ISP or a
third party. Note that having multiple ISPs can be motivation for
bandwidth aggregation or connectivity failover. In the case of
connectivity failover, the failover concerns the access network, and
a failure of the access network may not impact the core network where
the DM and Public Authoritative Primaries are hosted. In that sense,
choosing one of the ISPs even in a scenario of multiple ISPs may make
sense. However, for the sake of simplicity, this scenario assumes
that a third party has been chosen to host the Registered Homenet
Domain. Configuration is performed as described in Appendices A.2
and A.3.

With the configuration described in Appendix A.2, the HNA is expected
to be able to handle multiple Registered Homenet Domains as the
third-party redirect to one of the ISP's servers. With the
configuration described in Appendix A.3, DNS zones are hosted and
maintained by the third party. A single DNS(SEC) Homenet Zone is
built and maintained by the HNA. This latter configuration is likely
to match most HNA implementations.

The protocol and DHCPv6 options described in this document are fully
compatible with an HNA connected to multiple ISPs. Whether to
configure the HNA or not, and how to configure the HNA, depends on
the HNA facilities. Appendices A.1 and A.2 require the HNA to handle
multiple Registered Homenet Domains, whereas Appendix A.3 does not
have such a requirement.

Acknowledgments

We would like to thank Marcin Siodelski, Bernie Volz, and Ted Lemon
for their comments on the design of the DHCPv6 options. We would
also like to thank Mark Andrews, Andrew Sullivan, and Lorenzo Colliti
for their remarks on the architecture design. The designed solution
has been largely inspired by Mark Andrews's document [PD-REVERSE] as
well as discussions with Mark. We also thank Ray Hunter and Michael
Richardson for their reviews and comments and for suggesting
appropriate terminology.

Contributors

The coauthors would like to thank Chris Griffiths and Wouter Cloetens
for providing significant contributions to the early draft versions
of this document.

Authors' Addresses

Daniel Migault
Ericsson
8275 Trans Canada Route
Saint Laurent QC 4S 0B6
Canada
Email: [email protected]

Ralf Weber
Akamai
Email: [email protected]

Tomek Mrugalski
Internet Systems Consortium, Inc.
PO Box 360
Newmarket, NH 03857
United States of America
Email: [email protected]