Internet DRAFT - draft-ietf-homenet-front-end-naming-delegation
draft-ietf-homenet-front-end-naming-delegation
Homenet D. Migault
Internet-Draft Ericsson
Intended status: Experimental R. Weber
Expires: 12 August 2023 Nominum
M. Richardson
Sandelman Software Works
R. Hunter
Globis Consulting BV
8 February 2023
Simple Provisioning of Public Names for Residential Networks
draft-ietf-homenet-front-end-naming-delegation-27
Abstract
Home network owners may have devices or services hosted on their home
network that they wish to access from the Internet (i.e., from a
network outside of the home network). Home networks are increasingly
numbered using IPv6 addresses, which in principle makes this access
simpler, but their access from the Internet requires the names and IP
addresses of these devices and services to be made available in the
public DNS.
This document describes how an Home Naming Authority (NHA) instructs
the outsourced infrastructure to publish these pieces of information
in the public DNS. The names and IP addresses of the home network
are set in the Public Homenet Zone by the Homenet Naming Authority
(HNA), which in turn instructs an outsourced infrastructure to
publish the zone on behalf of the home network owner.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 12 August 2023.
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Copyright Notice
Copyright (c) 2023 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
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Selecting Names and Addresses to Publish . . . . . . . . . . 7
4. Envisioned deployment scenarios . . . . . . . . . . . . . . . 7
4.1. CPE Vendor . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. Agnostic CPE . . . . . . . . . . . . . . . . . . . . . . 9
5. Architecture Description . . . . . . . . . . . . . . . . . . 9
5.1. Architecture Overview . . . . . . . . . . . . . . . . . . 10
5.2. Distribution Manager (DM) Communication Channels . . . . 12
6. Control Channel . . . . . . . . . . . . . . . . . . . . . . . 13
6.1. Information to Build the Public Homenet Zone . . . . . . 14
6.2. Information to build the DNSSEC chain of trust . . . . . 15
6.3. Information to set up the Synchronization Channel . . . . 15
6.4. Deleting the delegation . . . . . . . . . . . . . . . . . 15
6.5. Messages Exchange Description . . . . . . . . . . . . . . 16
6.5.1. Retrieving information for the Public Homenet Zone . 16
6.5.2. Providing information for the DNSSEC chain of
trust . . . . . . . . . . . . . . . . . . . . . . . . 18
6.5.3. Providing information for the Synchronization
Channel . . . . . . . . . . . . . . . . . . . . . . . 18
6.5.4. HNA instructing deleting the delegation . . . . . . . 19
6.6. Securing the Control Channel . . . . . . . . . . . . . . 19
7. Synchronization Channel . . . . . . . . . . . . . . . . . . . 20
7.1. Securing the Synchronization Channel . . . . . . . . . . 21
8. DM Distribution Channel . . . . . . . . . . . . . . . . . . . 22
9. HNA Security Policies . . . . . . . . . . . . . . . . . . . . 22
10. Public Homenet Reverse Zone . . . . . . . . . . . . . . . . . 23
11. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 24
12. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 25
13. Privacy Considerations . . . . . . . . . . . . . . . . . . . 26
14. Security Considerations . . . . . . . . . . . . . . . . . . . 28
14.1. Registered Homenet Domain . . . . . . . . . . . . . . . 28
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14.2. HNA DM channels . . . . . . . . . . . . . . . . . . . . 28
14.3. Names are less secure than IP addresses . . . . . . . . 29
14.4. Names are less volatile than IP addresses . . . . . . . 30
14.5. Deployment Considerations . . . . . . . . . . . . . . . 30
14.6. Operational Considerations . . . . . . . . . . . . . . . 30
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31
16. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 31
17. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 31
18. References . . . . . . . . . . . . . . . . . . . . . . . . . 32
18.1. Normative References . . . . . . . . . . . . . . . . . . 32
18.2. Informative References . . . . . . . . . . . . . . . . . 33
Appendix A. HNA Channel Configurations . . . . . . . . . . . . . 37
A.1. Homenet Public Zone . . . . . . . . . . . . . . . . . . . 37
Appendix B. Information Model for Outsourced information . . . . 38
Appendix C. Example: A manufacturer provisioned HNA product
flow . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42
1. Introduction
Home network owners may have devices or services hosted on their home
network that they wish to access from the Internet (i.e., from a
network outside of the home network). The use of IPv6 addresesses in
the home makes in principle the actual network access simpler, while
on the other hand, the addresses are much harder to remember, and
subject to regular renumbering. To make this situation simpler for
typical home owners to manage, there needs to be an easy way for
names and IP addresses of these devices and services to be published
in the public DNS.
As depicted in {fig-outsourcing-overview}, he names and IP address of
the home network are made availble in the Public Homenet Zone by the
Homenet Naming Authority (HNA), which in turn instructs the DNS
Outsourcing Infrastructure (DOI) to publish the zone on behalf of the
HNA. This document describes how an HNA can instruct a DOI to
publish a Public Homenet Zone on its behalf.
The document introduces the Synchronization Channel and the Control
Channel between the HNA and the Distribution Manager (DM), which is
the main interface to the DNS Outsourcing Infrastructure (DOI).
The Synchronization Channel (see Section 7) is used to synchronize
the Public Homenet Zone.
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Internet
.---------------------. .-------------------.
| Home Network | Control | DOI |
|.-------------------.| Channel |.-----------------.|
|| HNA |<----------->| Distribution ||
||.-----------------.|| || Manager ||
||| Public Homenet ||| || ||
||| Zone ||<----------->| ||
||| myhome.example ||| Synchron- |'-----------------'|
||'-----------------'|| ization | | |
|'-------------------'| Channel | V |
| | |.-----------------.|
| | || Public Homenet ||
'---------------------' || Zone ||
|| myhome.example ||
|'-----------------'|
'---^--^--^--^--^---'
| | | | |
(served on the Internet)
Figure 1: High level architecture overview of outsourcing the
Public Homenet Zone
The Synchronization Channel is a zone transfer, with the HNA
configured as a primary, and the Distribution Manager configured as a
secondary. Some operators refer to this kind of configuration as a
"hidden primary", but that term is not used in this document as it is
not precisely defined anywhere, but has many slightly different
meanings to many.
The Control Channel (see Section 6) is used to set up the
Synchronization Channel. This channel is in the form of a dynamic
DNS update process, authenticated by TLS.
For example, to build the Public Homenet Zone, the HNA needs the
authoritative servers (and associated IP addresses) of the servers
(the visible primaries) of the DOI actually serving the zone.
Similarly, the DOI needs to know the IP address of the (hidden)
primary (HNA) as well as potentially the hash of the Key Signing Key
(KSK) in the DS RRset to secure the DNSSEC delegation with the parent
zone.
The remainder of the document is as follows.
Section 2 defines the terminology. Section 3 presents the general
problem of publishing names and IP addresses.
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Section 5 provides an architectural view of the HNA, DM and DOI as
well as their different communication channels (Control Channel,
Synchronization Channel, DM Distribution Channel) respectively
described in Section 6, Section 7 and Section 8.
Then Section 6 and Section 7 deal with the two channels that
interface to the home. Section 8 provides a set of requirements and
expectations on how the distribution system works. This section is
non-normative and not subject to standardization, but reflects how
many scalable DNS distribution systems operate.
Section 9 and Section 11 respectively detail HNA security policies as
well as DNSSEC compliance within the home network.
Section 12 discusses how renumbering should be handled.
Finally, Section 13 and Section 14 respectively discuss privacy and
security considerations when outsourcing the Public Homenet Zone.
The appendices discuss several management (see Section 10)
provisioning (see Section 10), configurations (see Appendix B) and
deployment (see Section 4 and Appendix C) aspects.
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. A given home network may have multiple
Registered Homenet Domain.
Public Homenet Zone: contains the names in the home network that are
expected to be publicly resolvable on the Internet. A home
network can have multiple Public Homenet Zones.
Homenet Naming Authority(HNA): is a function responsible for
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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.
Public Authoritative Servers: are the authoritative name servers for
the Public Homenet Zone. Name resolution requests for the
Registered Homenet Domain are sent to these servers. Some DNS
operators would refer to these as public secondaries, and for
higher resiliency networks, are often implemented in an anycast
fashion.
Homenet Authoritative Servers: are authoritative name servers for
the Homenet Zone within the Homenet network itself. These are
sometimes called the hidden primary servers.
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. This server has been historically known as the
Distribution Master.
Public 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 DNS(SEC) Resolver: a resolver that performs a DNS(SEC)
resolution on the home network for the Public Homenet Zone. The
resolution is performed requesting the Homenet Authoritative
Servers.
DNS(SEC) Resolver: a resolver that performs a DNS resolution on the
Internet for the Public Homenet Zone. The resolution is performed
requesting the Public Authoritative Servers.
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3. Selecting Names and Addresses to Publish
While this document does not create any normative mechanism to select
the names to publish, this document anticipates that the home network
administrator (a human being), will be presented with a list of
current names and addresses either directly on the HNA or via another
device such as a smartphone.
The administrator would mark which devices and services (by name),
are to be published. The HNA would then collect the IP address(es)
associated with that device or service, and put the name into the
Public Homenet Zone. The address of the device or service can be
collected from a number of places: mDNS [RFC6762], DHCP [RFC8415],
UPnP, PCP [RFC6887], or manual configuration.
A device or service SHOULD have Global Unicast Addresses (GUA) (IPv6
[RFC3787] or IPv4), but MAY also have Unique Local IPv6 Addresses
(ULA) [RFC4193], IPv6-Link-Local addresses[RFC4291][RFC7404], IPv4-
Link-Local Addresses [RFC3927] (LLA), and finally, private IPv4
addresses [RFC1918].
Of these the link-local are almost never useful for the Public Zone,
and should be omitted.
The IPv6 ULA and the private IPv4 addresses may be useful to publish,
if the home network environment features a VPN that would allow the
home owner to reach the network. RFC1918 addresses in public zones
are generally filtered out by many DNS servers as they are considered
rebind attacks [REBIND].
In general, one expects the GUA to be the default address to be
published. A direct advantage of enabling local communication is to
enable communications even in case of Internet disruption.
Since communications are established with names which remain a global
identifier, the communication can be protected (at the very least
with integrity protection) by TLS the same way it is protected on the
global Internet - using certificates.
4. Envisioned deployment scenarios
A number of deployment scenarios have been envisioned, this section
aims at providing a brief description. The use cases are not
limitations and this section is not normative.
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The main difference between the various deployments concerns the
provisioning of the HNA - that is how it is configured to outsource
the Public Homenet Zone to the DOI - as well as how the Public
Homenet Zone is being provisioned before being outsourced.
In both cases, these configuration aspects are out of the scope of
the document.
Provisioning the configuration related to the DOI is expected to be
automated as much as possible and require as little as possible
interaction with the end user.
Zero configuration can only be achieved under some circumstances and
[I-D.ietf-homenet-naming-architecture-dhc-options] provides one such
example under the assumption the ISP provides the DOI. Section 4.1
describes another variant where the CPE is provided preconfigured
with the DOI. Section 4.2 describes how an agnostic CPE may be
configured by the home network administrator. Of course even in this
case, the configuration can leverage mechanisms to prevent the end
user manually entering all information.
On the other hand, provisioning the Public Homenet Zone needs to
combine the ability to closely reflect what the end user wishes to
publish on the Internet while easing such interaction. The HNA may
implement such interactions using Web GUI or specific mobile
applications.
With the CPE configured with the DOI, the HNA contacts the DOI to
build a template for the Public Homenet Zone, and then provision the
Public Homenet Zone. Once the Public Homenet Zone is built, the HNA
strats synchronizing it with the DOI on the Synchronization channel.
4.1. CPE Vendor
A specific vendor with specific relations with a registrar or a
registry may sell a CPE that is provisioned with a domain name. Such
a domain name is probably not human friendly, and may consist of some
kind of serial number associated with the device being sold.
One possible scenario is that the vendor provisions the HNA with a
private key, with an associated certificate used for the mutual TLS
authentication. Note that these keys are not expected to be used for
DNSSEC signing.
Instead these keys are solely used by the HNA for the authentication
to the DM. Normally the keys should be necessary and sufficient to
proceed to the authentication.
When the home network owner plugs in the CPE at home, the relation
between HNA and DM is expected to work out-of-the-box.
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4.2. Agnostic CPE
A CPE that is not preconfigured may also use the protocol defined in
this document but some configuration steps will be needed.
1. The owner of the home network buys a domain name from a
registrar, and as such creates an account on that registrar
2. the registrar may also be providing the outsourcing
infrastructure or the home network may need to create a specific
account on the outsourcing infrastructure.
* If the DOI is the DNS 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. One potential mechanism
to provide the parameters would be to provide the user with a JSON
object which they can copy paste into the CPE - such as described
in Appendix B. But, what matters to infrastructure is that the
HNA is able to authenticate itself to the DOI.
* If the DOI is not the DNS Registrar, then the proof of ownership
needs to be established using some other protocol. ACME [RFC8555]
is one protocol that would allow an owner of an existing domain
name to prove their ownership (but requires they have DNS already
setup!) There are other ways such as putting a DOI generated TXT
record, or web site contents, as championed by entities like
Google's Sitemaster and Postmaster protocols.
[I-D.ietf-dnsop-domain-verification-techniques] describes a few
ways ownership or control of a domain can be achieved.
5. Architecture Description
This section provides an overview of the architecture for outsourcing
the authoritative naming service from the HNA to the DOI. As a
consequence, this prevents HNA to handle the DNS traffic from the
Internet associated with the resolution of the Homenet Zone.
The device assigned zone or user configurable zone to use as the
domain to publicly serve hostnames in the home network is called the
Public Homenet Zone. In this document, "myhome.example" is used as
the example for an enduser owned domain configured as Public Homenet
Zone.
More specifically, DNS resolution for the Public Homenet Zone (here
myhome.example) from Internet DNSSEC resolvers is handled by the DOI
as opposed to the HNA. The DOI benefits from a cloud infrastructure
while the HNA is dimensioned for home network and as such likely
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unable to support any load. In the case the HNA is a CPE,
outsourcing to the DOI reduces the attack surface of the home network
to DDoS for example. Of course the DOI needs to be informed
dynamically about the content of myhome.example. The description of
such a synchronization mechanism is the purpose of this document.
Note that Appendix B shows necessary parameters to configure the HNA.
5.1. Architecture Overview
.----------------------------. .-----------------------------.
| Home Network | | Internet |
| .-----------------------. | Control | .-----------------------. |
| | HNA | | Channel | | DOI | |
| | (hidden primary) |<------------->| (hidden secondary) | |
| | | | DNSUPD | | Distribution Manager | |
| | .-------------------. | | | | | |
| | | Public Homenet | | | | | .-------------------.| |
| | | Zone |<------------------>| Public Homenet Zo || |
| | | myhome.example | | |Synchron-| | | myhome.example || |
| | '-------------------' | | ization | | '-------------------'| |
| '-----------------------' |Channel | | | | |
| ^ | AXFR | | | | |
| | | | | v | |
| .-----------------------. | | |.---------------------.| |
| | Homenet Authoritative | | | || Public Authoriative || |
| | Server | | | || (secondary) Servers || |
| | + myhome.example | | | || + myhome.example || |
| | + home.arpa | | | || + x.y.z.ip6.arpa || |
| | + x.y.z.ip6.arpa | | | || || |
| '-----------------------' | | || || |
| | ^ | | |'---------------------'| |
| | | | | | ^ | | |
| | | | | '--|------------|-------' |
| v | | | | v |
| .----------------------. | | .------------------------. |
| | Homenet Resolver | | | | Internet Resolvers | |
| '----------------------' | | '------------------------' |
| | | |
'----------------------------' | |
'-----------------------------'
Figure 2: Homenet Naming Architecture
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Figure 2 illustrates the architecture where the HNA outsources the
publication of the Public Homenet Zone to the DOI. The DOI will
serve every DNS request of the Public Homenet Zone coming from
outside the home network. When the request is coming within the home
network, the resolution is expected to be handled by the Homenet
Resolver as detailed in further details below.
In this example, The Public Homenet Zone is identified by the
Registered Homenet Domain name -- myhome.example. This diagram also
shows a reverse IPv6 map being hosted.
The ".local" as well as ".home.arpa" are explicitly not considered as
Public Homenet zones and represented as a Homenet Zone in Figure 2.
They are resolved locally, but not published as they are local
content.
It is RECOMMENDED the HNA implements DNSSEC, in which case the HNA
MUST signs the Public Homenet Zone with DNSSEC.
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 communicates and
synchronizes it with the DOI using a primary/secondary setting as
depicted in Figure 2. The HNA acts as a stealth server (see
[RFC8499]) while the DM behaves as a hidden secondary. It is
responsible for distributing the Public Homenet Zone to the multiple
Public Authoritative Servers instances that DOI is responsible for.
The DM has three communication channels:
* DM Control Channel (Section 6) to configure the HNA and the DOI.
This includes necessary parameters to configure the primary/
secondary relation as well as some information provided by the DOI
that needs to be included by the HNA in the Public Homenet Zone.
* DM Synchronization Channel (Section 7) to synchronize the Public
Homenet Zone on the HNA and on the DM with the appropriately
configured primary/secondary. This is a zone transfer over
mutually authenticated TLS.
* one or more Distribution Channels (Section 8) that distribute the
Public Homenet Zone from the DM to the Public Authoritative
Servers serving the Public Homenet Zone on the Internet.
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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 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 DNS(SEC) resolvers. When the resolution
is performed outside the home network, the DNS(SEC) Resolver resolves
the DS record on the Global DNS and the name associated with the
Public Homenet Zone (myhome.example) on the Public Authoritative
Servers.
In order to provide resilience to the Public Homenet Zone in case of
WAN connectivity disruption, the Homenet DNS(SEC) Resolver MUST be
able to perform the resolution on the Homenet Authoritative Servers.
Note that the use of the Homenet resolver enhances privacy since the
user on the home network would no longer be leaking interactions with
internal services to an external DNS provider and to an on-path
observer. 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 DNS(SEC) Resolvers, e.g., using
HNCP [RFC7788] or a by configuring a trust anchor
[I-D.ietf-dnsop-dnssec-validator-requirements]. 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 2.
5.2. Distribution Manager (DM) Communication Channels
This section details the DM channels, that is the Control Channel,
the Synchronization Channel and the Distribution Channel.
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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.
Communications between the HNA and the DM MUST be protected and
mutually authenticated. Section 6.6 discusses in more depth the
different security protocols that could be used to secure.
The information exchanged between the HNA and the DM uses DNS
messages protected by DNS over TLS (DoT) [RFC7858]. This is
configured identically to that described in [RFC9103], Section 9.3.3.
It is worth noting that both DM and HNA need to agree on a common
configuration to set up the synchronization channel as well as to
build and server a coherent Public Homenet Zone. As previously
noted, the visible NS records of the Public Homenet Zone (built by
the HNA) remain pointing at the DOI's Public Authoritative Servers'
IP address. Unless the HNA is able to support the traffic load, the
HNA SHOULD NOT appear as a visible NS records of the Public Homenet
Zone. In addition, and depending on the configuration of the DOI,
the DM also needs to update the parent zone's NS, DS and associated A
or AAAA glue records. Refer to Section 6.2 for more details.
This specification assumes:
* the DM serves both the Control Channel and Synchronization Channel
on a single IP address, single port and using a single transport
protocol.
* 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 7 and Section 6.3 for more details.
The Distribution Channel is internal to the DOI and as such is not
normatively defined by this specification.
6. 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 6.1),
information to build the DNSSEC chain of trust (Section 6.2) and
information to set the Synchronization Channel (Section 6.3).
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Some information is carried from the DOI to the HNA, described in the
next section. The HNA updates the DOI with the the IP address on
which the zone is to be transferred using the synchronization
channel. The HNA is always initiating the exchange in both
directions.
As such the HNA has a prior knowledge of the DM identity (via X509
certificate), the IP address and port number to use and protocol to
establish a secure session. The DM acquires 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 Appendix A.1.
6.1. Information to Build the Public Homenet Zone
The HNA builds the Public Homenet Zone based on a template that is
returned by the DM to the HNA. Section 6.5 explains how this
leverages the AXFR mechanism.
In order to build its zone completely, the HNA needs the names (and
possibly IP addresses) of the Public Authoritative Name Servers.
These are used to populate the NS records for the zone. All the
content of the zone MUST be created by the HNA, because the zone is
DNSSEC signed.
In addition, the HNA needs to know what to put into the MNAME of the
SOA, and only the DOI knows what to put there. The DM MUST also
provide useful operational parameters such as other fields of SOA
(SERIAL, RNAME, REFRESH, RETRY, EXPIRE and MINIMUM), however, the HNA
is free to override these values based upon local configuration. For
instance, an HNA might want to change these values if it thinks that
a renumbering event is approaching.
As the information is necessary for the HNA to proceed and the
information is associated with the DM, this information exchange is
mandatory.
The HNA then performs a DNS Update operation to the DOI, updating the
DOI with an NS, DS, A and AAAA records. These indicates where its
Synchronization Channel is. The DOI does not publish this NS record,
but uses it to perform zone transfers.
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6.2. Information to build the DNSSEC chain of trust
The HNA MUST provide the hash of the KSK via the DS RRset, so that
the DOI can provide 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 to advertise the DS to the
parent zone. On the other hand if the DM does not have the capacity
to advertise the DS to the parent zone, it indicates this by refusing
the update to the DS RR.
6.3. Information to set up the Synchronization Channel
The HNA works as a hidden primary authoritative DNS server, while the
DM works like a secondary. As a result, the HNA needs to provide the
IP address the DM should use to reach the HNA.
If the HNA detects that it has been renumbered, then it MUST use the
Control Channel to update the DOI with the new IPv6 address it has
been assigned.
The Synchronization Channel will be set between the new IPv6 (and
IPv4) 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 explicit 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.
6.4. 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.
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Section 6.5.4 explains how a DNS Update operation on the Control
Channel is used.
Upon an instruction of deleting the delegation, the DM MUST stop
serving the Public Homenet Zone.
The decision to delete an inactive HNA by the DM is part of the
commercial agreement between DOI and HNA.
6.5. Messages Exchange Description
Multiple ways were considered on how the control information could be
exchanged between the HNA and the DM.
This specification defines a mechanism that re-uses the DNS zone
transfer format. 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 used as commands between the
HNA and the DM. This was found to be simpler on the home router
side, as the HNA already has to have code to deal with all the DNS
encodings/decodings. Inventing a new way to encode the DNS
information in, for instance, JSON, seemed to add complexity for no
return on investment.
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 use of a TLS session tickets [RFC8446], Section 4.6.1 is
RECOMMENDED.
The authentication of the channel MUST 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.
6.5.1. 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.
To retrieve the necessary information to build the Public Homenet
Zone, the HNA MUST send a DNS request of type AXFR associated with
the Registered Homenet Domain.
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The zone that is returned by the DM is used by the HNA as a template
to build its own zone.
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 (if the NS
are in-domain [RFC8499]). The zone template will include Time To
Live (TTL) values for each RR, and the HNA SHOULD take these as
suggested maximum values, but MAY use lower values for operational
reasons, such impending renumbering events.
* The SOA RR indicates to the HNA the value of the MNAME of the
Public Homenet Zone.
* The NAME of the SOA RR MUST be the Registered Homenet Domain.
* The MNAME value of the SOA RDATA is the value provided by the DOI
to the HNA.
* 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.
In addition to the considerations above about default TTL, the HNA
SHOULD take care to not pick a TTL larger than the parent NS, based
upon resolver's guide lines: [I-D.ietf-dnsop-ns-revalidation] and
[I-D.ietf-dnsop-dnssec-validator-requirements]. 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
MUST not exceed the values 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.
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6.5.2. 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 [RFC3007] message.
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 MUST ignore the Pre-requisite and Additional Data
sections, if present. 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 DM does not
update the DS, and the HNA needs to act accordingly or other method
should be used by the HNA.
The regular DNS error message MUST 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.
6.5.3. 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 6.5.2, 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
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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 with the primary (or the HNA).
The reason to provide these IP addresses is to keep them unpublished
and prevent them to be resolved. It is RECOMMENDED the IP address of
the HNA is randomly chosen to prevent it from being easily discovered
as well.
Upon receiving the DNS update request, the DM reads the IP addresses
and checks the ZNAME corresponds to the parent zone. The DM MUST
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 6.5.2, DNS errors are used and an error
indicates the DM is not configured as a secondary.
6.5.4. HNA instructing deleting the delegation
To instruct to delete the delegation the HNA sends 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 6.5.2, DNS errors are used and an error indicates the
delegation has not been deleted.
6.6. Securing the Control Channel
TLS [RFC8446]) MUST be used to secure the transactions between the DM
and the HNA and the DM and HNA MUST be mutually authenticated. The
DNS exchanges are performed using DNS over TLS [RFC7858].
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The HNA may be provisioned by the manufacturer, or during some user-
initiated onboarding process, for example, with a browser, signing up
to a service provider, with a resulting OAUTH2 token to be provided
to the HNA. Such a process may result in a passing of a settings
from a Registrar into the HNA through an http API interface. (This
is not in scope)
When the HNA connects to the DM's control channel, TLS will be used,
and the connection will be mutually authenticated. The DM will
authenticate the HNA's certificate based upon having participating in
some provisioning process that is not standardized by this document.
The results of the provisioning process is a series of settings
described in Appendix A.1.
The HNA will validate the DM's control channel certificate by doing
an [I-D.ietf-uta-rfc6125bis] DNS-ID check on the name.
In the future, 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
[RFC9250].
7. 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. Suppose the HNA and the DM are using a single IP
address and let designate by XX. YYYYY and ZZZZZ the various ports
involved in the communications.
The Control Channel is between the HNA working as a client using port
number YYYYY (an ephemeral also commonly designated as high range
port) toward a service provided by the DM at port 853, when using
DoT.
On the other hand, the Synchronization Channel is set between the DM
working as a client using port ZZZZZ (another ephemeral port) toward
a service provided by the HNA at port 853.
As a result, even though the same pair of IP addresses may be
involved the Control Channel and the Synchronization Channel are
always distinct channels.
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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 is handled using the normal zone transfer
mechanism involving AXFR/IXFR.
Part of this zone update process involves the owner of the zone (the
hidden primary, the HNA) sending a DNS Notify to the secondaries. In
this situation the only destination that is known by the HNA is the
DM's Control Channel, and so DNS notifies are sent over the Control
Channel, secured by a mutually authenticated TLS.
Please note that, DNS Notifies are not critical to normal operation,
as the DM will be checking the zone regularly based upon SOA record
comments. DNS Notifies do speed things up as they cause the DM to
use the Synchronization channel to immediately do an SOA Query to
detect any updates. If there are any changes then the DM immediately
transfers the zone updates.
This specification standardizes the use of a primary / secondary
mechanism [RFC1996] rather than an extended series of DNS update
messages. The primary / secondary mechanism was selected as it
scales better and avoids DoS attacks. As this AXFR runs over a TCP
channel secured by a mutually authenticated TLS, then DNS Update is
just more complicated.
Note that this document provides 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 for future work.
7.1. Securing the Synchronization Channel
The Synchronization Channel uses mutually authenticated TLS, as
described by [RFC9103].
There is a TLS client certificate used by the DM to authenticate
itself. The DM uses the same certificate which was configured into
the HNA for authenticating the Control Channel, but as a client
certificate rather than a server certificate.
[RFC9103] makes no requirements or recommendations on any extended
key usage flags for zone transfers, and this document adopts the view
that none should be required. and leave it up to [RFC9103] to get
updated for this document's normative reference to be considered
updated as well.
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For the TLS server certificate, the HNA uses the same certificate
which it uses to authenticate itself to the DM for the Control
Channel.
The HNA MAY use this certificate as the authorization for the zone
transfer, or the HNA MAY have been configured with an Access Control
List that will determine if the zone transfer can proceed. This is a
local configuration option, as it is premature to determine which
will be operationally simpler.
When the HNA expects to do zone transfer authorization by certificate
only, the HNA MAY still apply an ACL on inbound connection requests
to avoid load. In this case, the HNA MUST regularly check (via a DNS
resolution) that the address(es) of the DM in the filter is still
valid.
8. 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 are outside the
scope of this document, and there are many existing solutions
available, e.g., rsync, DNS AXFR, REST, DB copy.
9. HNA Security Policies
The HNA as hidden primary processes only a limited message exchanges
on it's Internet facing interface. This should be enforced using
security policies - to allow only a subset of DNS requests to be
received by HNA.
The Hidden Primary Server on the HNA differs the 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. This results in a limited number of possible
exchanges (AXFR/IXFR) with a small number of IP addresses and an
implementation MUST enable filtering policies: it should only
respond to queries that are required to do zone transfers. That
list includes SOA queries and AXFR/IXFR queries.
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10. Public Homenet Reverse Zone
Public Homenet Reverse Zone works similarly to the Public Homenet
Zone. The main difference is that ISP that provides the IPv6
connectivity is likely also the owner of the corresponding IPv6
reverse zone and administrating the Reverse Public Authoritative
Servers. The configuration and the setting of the Synchronization
Channel and Control Channel can largely be automated using DHCPv6
messages that are part of the IPv6 Prefix Delegation process.
The Public Homenet Zone is associated with 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 as the ISP owns the IP
address or IP prefix.
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 leaves place for setting up automatically the relation between
HNA and the DOI 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.
Exceptionally, the synchronization channel might be from a different
zone delegated to the HNA (if there were multiple zones, or
renumbering events were in progress).
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.
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An ISP that has delegated 2001:db8:aeae::/56 to the HNA via
DHCPv6-PD, then HNA should originate Synchronization Channel updates
an IP within that subnet, such as 2001:db8:aeae:1::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 with 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 with 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 reverse domain space for IP addresses associated with
a subnet such as ::/64 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.
11. 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. Other documents such
as [RFC5011] deal with continuous update of trust anchors required
for operation of a DNSSEC resolver.
The HNA MUST DNSSEC sign the Public Homenet Zone and the Public
Reverse Zone.
Secure delegation is achieved only if the DS RRset is properly set in
the parent zone. Secure delegation can be performed by the HNA or
the DOIs and the choice highly depends on which entity is authorized
to perform such updates. Typically, the DS RRset is updated manually
through a registrar interface, and can be maintained with mechanisms
such as CDS [RFC7344].
When the operator of the DOI is also the Registrar for the domain,
then it is a trivial matter for the DOI to initialize the relevant DS
records in the parent zone. In other cases, some other
initialization will be required, and that will be specific to the
infrastructure involved. It is beyond the scope of this document.
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There may be some situations where the HNA is unable to arrange for
secure delegation of the zones, but the HNA MUST still sign the
zones.
12. Renumbering
During a renumbering of the home network, the HNA IP address may be
changed and the Public Homenet Zone will be updated by the HNA with
new AAAA records.
The HNA will then advertise to the DM via a NOTIFY on the Control
Channel. The DM will need to note the new originating IP for the
connection, and it will need to update it's internal database of
Synchronization Channels. A new zone transfer will occur with the
new records for the resources that the HNA wishes to publish.
The remaining of the section provides recommendations regarding the
provisioning of the Public Homenet Zone - especially the IP
addresses.
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. 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. New resources records containing the new prefix
SHOULD be published, while the old resource records with the old
prefixes SHOULD be withdrawn. If the HNA anticipates that period of
overlap is long (perhaps due to knowledge of router and DHCPv6
lifetimes), it MAY publish the old prefixes with a significantly
lower time to live.
In break-before-make renumbering scenarios, including flash
renumbering scenarios [RFC8978], the old prefix becomes unuseable
before the new prefix is known or advertised. As explained in
[RFC8978], some flash renumberings occur due to power cycling of the
HNA, where ISPs do not properly remember what prefixes have been
assigned to which user.
An HNA that boots up MUST immediately use the Control Channel to
update the location for the Synchronization Channel. This is a
reasonable thing to do on every boot, as the HNA has no idea how long
it has been offline, or if the (DNSSEC) zone has perhaps expired
during the time the HNA was powered off.
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The HNA will have a list of names that should be published, but it
might not yet have IP addresses for those devices. This could be
because at the time of power on, the other devices are not yet
online. If the HNA is sure that the prefix has not changed, then it
should use the previously known addresses, with a very low TTL.
Although the new and old IP addresses may be stored in the Public
Homenet Zone, it is RECOMMENDED that only the newly reachable IP
addresses be published.
Regarding the Public Homenet Reverse Zone, the new Public Homenet
Reverse Zone has to be populated as soon as possible, and the old
Public Homenet Reverse Zone will be deleted by the owner of the zone
(and the owner of the old prefix which is usually the ISP) once the
prefix is no longer assigned to the HNA. The ISP MUST ensure that
the DNS cache has expired before re-assigning the prefix to a new
home network. This may be enforced by controlling the TTL values.
To avoid reachability disruption, IP connectivity information
provided by the DNS MUST be coherent with the IP in use. In our
case, this means the old IP address MUST NOT be provided via the DNS
when it is not reachable anymore.
In the make-before-break scenario, it is possible to make the
transition seamless. Let T be the TTL associated with a RRset of the
Public Homenet Zone. Let Time_NEW be the time the new IP address
replaces the old IP address in the Homenet Zone, and
Time_OLD_UNREACHABLE the time the old IP will not be reachable
anymore.
In the case of the make-before-break, seamless reachability is
provided as long as Time_OLD_UNREACHABLE - T_NEW > (2 * T). If this
is not satisfied, then devices associated with the old IP address in
the home network may become unreachable for 2 * T -
(Time_OLD_UNREACHABLE - Time_NEW).
In the case of a break-before-make, Time_OLD_UNREACHABLE = Time_NEW,
and the device may become unreachable up to 2 * T. Of course if
Time_NEW >= Time_OLD_UNREACHABLE, then then outage is not seamless.
13. 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
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able to walk the zone, to discover all the names. However, recent
work [GPUNSEC3] or [ZONEENUM] have shown that the protection provided
by NSEC3 against dictionary attacks should be considered cautiously
and [RFC9276] provides guidelines to configure NSEC3 properly. In
addition, the attacker may be able to walk the reverse DNS zone, or
use other reconnaissance techniques to learn this information as
described in [RFC7707].
The zone may be also exposed during the synchronization between the
primary and the secondary. The casual risk of this occuring is low,
and the use of [RFC9103] significantly reduces this. Even if
[RFC9103] is used by the DNS Outsourcing Infrastructure, it may still
leak the existence of the zone through Notifies. The protocol
described in this document does not increase that risk, as all
Notifies use the encrypted Control Channel.
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, and for privacy reasons, the home network owner wished
publish names only for services that 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 main
advantages of publishing the name are that service may be access by
the same name both within the home and outside the home and that the
DNS resolution can be handled similarly within the home and outside
the home. This considerably eases the ability to use VPNs where the
VPN can be chosen according to the IP address of the service.
Typically, a user may configure its device to reach its homenet
devices via a VPN while the remaining of the traffic is accessed
directly.
Enterprise networks have generally adopted another strategy
designated as split-horizon-DNS. While such strategy might appear as
providing more privacy at first sight, its implementation remains
challenging and the privacy advantages needs to be considered
carefully. In split-horizon-DNS, names are designated with internal
names that can only be resolved within the corporate network. When
such strategy is applied to homenet, VPNs needs to be both configured
with a naming resolution policies and routing policies. Such
approach might be reasonable with a single VPN, but maintaining a
coherent DNS space and IP space among various VPNs comes with serious
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complexities. Firstly, if multiple homenets are using the same
domain name -- like home.arpa -- it becomes difficult to determine on
which network the resolution should be performed. As a result,
homenets should at least be differentiated by a domain name.
Secondly, the use of split-horizon-DNS requires each VPN being
associated with a resolver and specific resolutions being performed
by the dedicated resolver. Such policies can easily raises some
conflicts (with significant privacy issues) while remaining hard to
be implemented.
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,
caching may obfuscate this information inside the home network, it is
likely that outside your home network this information will not be
cached.
14. Security Considerations
The HNA never answers DNS requests from the Internet. These requests
are instead served by the DOI.
While this limits the level of exposure of the HNA, the HNA still has
some exposure to attacks from the Internet. This section analyses
the attack surface associated with these communications, the data
published by the DOI, as well as operational considerations.
14.1. Registered Homenet Domain
The DOI MUST NOT serve any Public Homenet Zone that it has not strong
confidence the HNA owns the Registered Homenet Domain. Proof of
ownership is outside the document and is assumed such phase has
preceded the outsourcing of the zone.
14.2. HNA DM channels
The channels between HNA and DM are mutually authenticated and
encrypted with TLS [RFC8446] and its associated security
considerations apply.
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To ensure the multiple TLS session are continuously authenticating
the same entity, TLS may take advantage of second factor
authentication as described in [RFC8672] for the TLS server
certificate for the Control Channel. The HNA should also cache the
TLS server certificate used by the DM, in order to authenticate the
DM during the setup of the Synchronization Channel. (Alternatively,
the HNA is configured with an ACL from which Synchronization Channel
connections will originate)
The Control Channel and the Synchronization Channel respectively
follow [RFC7858] and [RFC9103] guidelines.
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 Reverse Distribution Manager (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.
14.3. Names are less secure than IP addresses
This document describes how an end user can make their services and
devices from their 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. IPv4 Addresses are 4 bytes long leading to 2**32
possibilities. With IPv6 addresses, the Interface Identifier is 64
bits long leading to up to 2^64 possibilities for a given 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.
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14.4. 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. In addition IPv6 enables temporary
addresses that makes them even more volatile [RFC8981]. 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 PTR DNS queries and MAY instead be configured to return
with NXDOMAIN.
14.5. Deployment Considerations
The HNA is expected to sign the DNSSEC zone and as such hold the
private KSK/ZSK.
There is no strong justification in this case to use a separate KSK
and ZSK. If an attacker can get access to one of them, it likely
that they will access both of them. If the HNA is run in a home
router with a secure element (SE) or TPM, storing the private keys in
the secure element would be a useful precaution. The DNSSEC keys are
generally needed on an hourly to weekly basis, but not more often.
While there is some risk that the DNSSEC keys might be disclosed by
malicious parties, the bigger risk is that they will simply be lost
if the home router is factory reset, or just thrown out/replaced with
a newer model.
Generating new DNSSEC keys is relatively easy, they can be deployed
using the Control Channel to the DM. The key that is used to
authenticate that connection is the critical key that needs
protection, and should ideally be backed up to offline storage.
(Such as a USB key)
14.6. Operational Considerations
HomeNet technologies makes it easier to expose devices and services
to the Internet. This imposes broader operational considerations for
the operator and the Internet:
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* The home network operator must carefully assess whether a device
or service previously fielded only on a home network is robust
enough to be exposed to the Internet
* The home network operator will need to increase the diligence to
regularly managing these exposed devices due to their increased
risk posture of being exposed to the Internet
* Depending on the operational practices of the home network
operators, there is an increased risk to the Internet through the
possible introduction of additional internet-exposed system that
are poorly managed and likely to be compromised.
15. IANA Considerations
This document has no actions for IANA.
16. Acknowledgment
The authors wish to thank Philippe Lemordant for his 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, Stephen Farrell, 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.
The authors would like to thank Kiran Makhijani for her in-depth
review that contributed in shaping the final version.
The authors would like to thank our Area Directorate Éric Vyncke for
his constant support and pushing the document through the IESG as
well as the many reviewers from various directorates including
Anthony Somerset, Geoff Huston, Tim Chown, Tim Wicinski, Matt Brown,
Darrel Miller, Chirster Holmberg.
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-uta-rfc6125bis]
Saint-Andre, P. and R. Salz, "Service Identity in TLS",
Work in Progress, Internet-Draft, draft-ietf-uta-
rfc6125bis-10, 25 January 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-uta-
rfc6125bis-10>.
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/rfc/rfc1034>.
[RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.
J., and E. Lear, "Address Allocation for Private
Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918,
February 1996, <https://www.rfc-editor.org/rfc/rfc1918>.
[RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone
Changes (DNS NOTIFY)", RFC 1996, DOI 10.17487/RFC1996,
August 1996, <https://www.rfc-editor.org/rfc/rfc1996>.
[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/rfc/rfc2119>.
[RFC3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic
Update", RFC 3007, DOI 10.17487/RFC3007, November 2000,
<https://www.rfc-editor.org/rfc/rfc3007>.
[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/rfc/rfc4034>.
[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/rfc/rfc5155>.
[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/rfc/rfc7344>.
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[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/rfc/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/rfc/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/rfc/rfc8375>.
[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/rfc/rfc8446>.
[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/rfc/rfc8499>.
[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/rfc/rfc9103>.
18.2. Informative References
[GPUNSEC3] Wander, M., Schwittmann, L., Boelmann, C., and T. Weis,
"GPU-Based NSEC3 Hash Breaking", n.d.,
<https://doi.org/10.1109/NCA.2014.27>.
[I-D.ietf-dnsop-dnssec-validator-requirements]
Migault, D., Lewis, E., and D. York, "Recommendations for
DNSSEC Resolvers Operators", Work in Progress, Internet-
Draft, draft-ietf-dnsop-dnssec-validator-requirements-04,
25 January 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-dnsop-dnssec-validator-requirements-04>.
[I-D.ietf-dnsop-domain-verification-techniques]
Sahib, S. K., Huque, S., and P. Wouters, "Survey of Domain
Verification Techniques using DNS", Work in Progress,
Internet-Draft, draft-ietf-dnsop-domain-verification-
techniques-00, 28 July 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-
domain-verification-techniques-00>.
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[I-D.ietf-dnsop-ns-revalidation]
Huque, S., Vixie, P. A., and R. Dolmans, "Delegation
Revalidation by DNS Resolvers", Work in Progress,
Internet-Draft, draft-ietf-dnsop-ns-revalidation-03, 6
September 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-dnsop-ns-revalidation-03>.
[I-D.ietf-homenet-naming-architecture-dhc-options]
Migault, D., Weber, R., and T. Mrugalski, "DHCPv6 Options
for Home Network Naming Authority", Work in Progress,
Internet-Draft, draft-ietf-homenet-naming-architecture-
dhc-options-24, 31 October 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-homenet-
naming-architecture-dhc-options-24>.
[I-D.richardson-homerouter-provisioning]
Richardson, M., "Provisioning Initial Device Identifiers
into Home Routers", Work in Progress, Internet-Draft,
draft-richardson-homerouter-provisioning-02, 14 November
2021, <https://datatracker.ietf.org/doc/html/draft-
richardson-homerouter-provisioning-02>.
[REBIND] "DNS rebinding", n.d.,
<https://en.wikipedia.org/wiki/DNS_rebinding>.
[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/rfc/rfc2136>.
[RFC3787] Parker, J., Ed., "Recommendations for Interoperable IP
Networks using Intermediate System to Intermediate System
(IS-IS)", RFC 3787, DOI 10.17487/RFC3787, May 2004,
<https://www.rfc-editor.org/rfc/rfc3787>.
[RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
Configuration of IPv4 Link-Local Addresses", RFC 3927,
DOI 10.17487/RFC3927, May 2005,
<https://www.rfc-editor.org/rfc/rfc3927>.
[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/rfc/rfc4192>.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005,
<https://www.rfc-editor.org/rfc/rfc4193>.
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[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/rfc/rfc4291>.
[RFC5011] StJohns, M., "Automated Updates of DNS Security (DNSSEC)
Trust Anchors", STD 74, RFC 5011, DOI 10.17487/RFC5011,
September 2007, <https://www.rfc-editor.org/rfc/rfc5011>.
[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/rfc/rfc6092>.
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012,
<https://www.rfc-editor.org/rfc/rfc6749>.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013,
<https://www.rfc-editor.org/rfc/rfc6762>.
[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/rfc/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/rfc/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/rfc/rfc7084>.
[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/rfc/rfc7368>.
[RFC7404] Behringer, M. and E. Vyncke, "Using Only Link-Local
Addressing inside an IPv6 Network", RFC 7404,
DOI 10.17487/RFC7404, November 2014,
<https://www.rfc-editor.org/rfc/rfc7404>.
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[RFC7707] Gont, F. and T. Chown, "Network Reconnaissance in IPv6
Networks", RFC 7707, DOI 10.17487/RFC7707, March 2016,
<https://www.rfc-editor.org/rfc/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/rfc/rfc7788>.
[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/rfc/rfc8094>.
[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/rfc/rfc8415>.
[RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS
(DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
<https://www.rfc-editor.org/rfc/rfc8484>.
[RFC8501] Howard, L., "Reverse DNS in IPv6 for Internet Service
Providers", RFC 8501, DOI 10.17487/RFC8501, November 2018,
<https://www.rfc-editor.org/rfc/rfc8501>.
[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/rfc/rfc8555>.
[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/rfc/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/rfc/rfc8672>.
[RFC8978] Gont, F., Žorž, J., and R. Patterson, "Reaction of IPv6
Stateless Address Autoconfiguration (SLAAC) to Flash-
Renumbering Events", RFC 8978, DOI 10.17487/RFC8978, March
2021, <https://www.rfc-editor.org/rfc/rfc8978>.
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[RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves,
"Temporary Address Extensions for Stateless Address
Autoconfiguration in IPv6", RFC 8981,
DOI 10.17487/RFC8981, February 2021,
<https://www.rfc-editor.org/rfc/rfc8981>.
[RFC9250] Huitema, C., Dickinson, S., and A. Mankin, "DNS over
Dedicated QUIC Connections", RFC 9250,
DOI 10.17487/RFC9250, May 2022,
<https://www.rfc-editor.org/rfc/rfc9250>.
[RFC9276] Hardaker, W. and V. Dukhovni, "Guidance for NSEC3
Parameter Settings", BCP 236, RFC 9276,
DOI 10.17487/RFC9276, August 2022,
<https://www.rfc-editor.org/rfc/rfc9276>.
[ZONEENUM] Wang, Z., Xiao, L., and R. Wang, "An efficient DNSSEC zone
enumeration algorithm", n.d..
Appendix A. HNA Channel Configurations
A.1. Homenet Public Zone
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.
The HNA needs to be provisioned with:
* the Registered Domain (e.g., myhome.example )
* 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
* the DM transport protocol and port (the default is DNS over TLS,
on port 853)
* 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
CPE, 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 6.5.3 when the NS and A or AAAA RRsets are communicated.
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The above parameters MUST be be provisioned for ISP-specific reverse
zones. One example of how to do this can be found in
[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 with 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.
Appendix B. Information Model for Outsourced information
This section 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.
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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.
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....",
}
Registered Homenet Domain (registered_domain) 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.
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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.
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
method 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 DOI consists of a number of
different systems. An array of addresses is permitted. This
parameter is optional and if unspecified, the CPE uses the IP
addresses provided by the dm parameter either directly when dm
indicates an IP address or the IP addresses returned by the
DNS(SEC) resolution when dm indicates 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.
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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
serial number (see Appendix C 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.
Appendix C. 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:
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{
"dm" : "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.
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
United States of America
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
5632CW Eindhoven
Netherlands
Email: v6ops@globis.net
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