draft-ietf-homenet-front-end-naming-delegation-08.txt   draft-ietf-homenet-front-end-naming-delegation-09.txt 
Homenet D. Migault Homenet D. Migault
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Informational R. Weber Intended status: Informational R. Weber
Expires: November 11, 2019 Nominum Expires: May 20, 2020 Nominum
M. Richardson
Sandelman Software Works
R. Hunter R. Hunter
Globis Consulting BV Globis Consulting BV
C. Griffiths C. Griffiths
W. Cloetens W. Cloetens
SoftAtHome< SoftAtHome
May 10, 2019 November 17, 2019
Outsourcing Home Network Authoritative Naming Service Outsourcing Home Network Authoritative Naming Service
draft-ietf-homenet-front-end-naming-delegation-08 draft-ietf-homenet-front-end-naming-delegation-09
Abstract Abstract
Designation of services and devices of a home network is not user The Homenet Naming authority is responsible for making devices within
friendly, and mechanisms should enable a user to designate services the home network accessible by name within the home network as well
and devices inside a home network using names. as from outside the home network (e.g. the Internet). The names of
the devices accessible from the Internet are stored in the Public
In order to enable internal communications while the home network Homenet Zone, served by a DNS authoritative server. It is unlikely
experiments Internet connectivity shortage, the naming service should that home networks will contain sufficiently robust platforms
be hosted on a device inside the home network. On the other hand, designed to host a service such as the DNS on the Internet and as
home networks devices have not been designed to handle heavy loads. such would expose the home network to DDoS attacks.
As a result, hosting the naming service on such home network device,
visible on the Internet exposes this device to resource exhaustion
and other attacks, which could make the home network unreachable, and
most probably would also affect the internal communications of the
home network.
As result, home networks may prefer not serving the naming service This document describes a mechanism that enables the Home Network
for the Internet, but instead prefer outsourcing it to a third party.
This document describes a mechanisms that enables the Home Network
Authority (HNA) to outsource the naming service to the Outsourcing Authority (HNA) to outsource the naming service to the Outsourcing
Infrastructure. Infrastructure via a Distribution Master (DM).
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 20, 2020.
This Internet-Draft will expire on November 11, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Alternative solutions . . . . . . . . . . . . . . . . . . 5
4. Architecture Description . . . . . . . . . . . . . . . . . . 6 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 6 4. Architecture Description . . . . . . . . . . . . . . . . . . 7
4.2. Example: Homenet Zone . . . . . . . . . . . . . . . . . . 8 4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 7
4.3. Example: HNA necessary parameters for outsourcing . . . . 10 4.2. Distribution Master Communication Channels . . . . . . . 10
5. Synchronization between HNA and the Synchronization Server . 11 5. Control Channel between HNA and DM . . . . . . . . . . . . . 11
5.1. Synchronization with a Hidden Primary . . . . . . . . . . 12 5.1. Information to build the Public Homenet Zone. . . . . . . 11
5.2. Securing Synchronization . . . . . . . . . . . . . . . . 13 5.2. Information to build the DNSSEC chain of trust. . . . . . 12
5.3. HNA Security Policies . . . . . . . . . . . . . . . . . . 14 5.3. Information to set the Synchronization Channel, . . . . . 12
6. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 14 5.4. Deleting the delegation . . . . . . . . . . . . . . . . . 13
6.1. Zone Signing" . . . . . . . . . . . . . . . . . . . . . . 15 5.5. Messages Exchange Description . . . . . . . . . . . . . . 13
6.2. Secure Delegation" . . . . . . . . . . . . . . . . . . . 16 5.5.1. Retrieving information for the Public Homenet Zone. . 13
7. Handling Different Views . . . . . . . . . . . . . . . . . . 17 5.5.2. Providing information for the DNSSEC chain of trust . 14
7.1. Misleading Reasons for Local Scope DNS Zone" . . . . . . 17 5.5.3. Providing information for the Synchronization Channel 14
7.2. Consequences" . . . . . . . . . . . . . . . . . . . . . . 18 5.5.4. HNA instructing deleting the delegation . . . . . . . 15
7.3. Guidance and Recommendations . . . . . . . . . . . . . . 19 5.6. Securing the Control Channel between HNA and DM . . . . . 15
7.4. Homenet Reverse Zone . . . . . . . . . . . . . . . . . . 19 5.7. Implementation Tips . . . . . . . . . . . . . . . . . . . 16
8. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 19 6. DM Synchronization Channel between HNA and DM . . . . . . . . 17
8.1. Hidden Primary . . . . . . . . . . . . . . . . . . . . . 20 6.1. Securing the Synchronization Channel between HNA and DM . 18
8.2. Synchronization Server . . . . . . . . . . . . . . . . . 21 7. DM Distribution Channel . . . . . . . . . . . . . . . . . . . 18
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22 8. HNA Security Policies . . . . . . . . . . . . . . . . . . . . 18
10. Security Considerations . . . . . . . . . . . . . . . . . . . 23 9. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 19
10.1. Names are less secure than IP addresses . . . . . . . . 23 10. Homenet Reverse Zone . . . . . . . . . . . . . . . . . . . . 19
10.2. Names are less volatile than IP addresses . . . . . . . 23 11. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 20
10.3. DNS Reflection Attacks . . . . . . . . . . . . . . . . . 24 11.1. Hidden Primary . . . . . . . . . . . . . . . . . . . . . 20
10.4. "Reflection Attack involving the Hidden Primary . . . . 24 11.2. Distribution Master . . . . . . . . . . . . . . . . . . 21
10.5. Reflection Attacks involving the Synchronization Server 25 12. Operational considerations for Offline/Disconnected
10.6. Reflection Attacks involving the Public Authoritative resolution . . . . . . . . . . . . . . . . . . . . . . . . . 22
13. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22
14. Security Considerations . . . . . . . . . . . . . . . . . . . 23
14.1. HNA DM channels . . . . . . . . . . . . . . . . . . . . 23
14.2. Names are less secure than IP addresses . . . . . . . . 23
14.3. Names are less volatile than IP addresses . . . . . . . 23
14.4. DNS Reflection Attacks . . . . . . . . . . . . . . . . . 23
14.5. Reflection Attack involving the Hidden Primary . . . . . 24
14.6. Reflection Attacks involving the DM . . . . . . . . . . 25
14.7. Reflection Attacks involving the Public Authoritative
Servers . . . . . . . . . . . . . . . . . . . . . . . . 26 Servers . . . . . . . . . . . . . . . . . . . . . . . . 26
10.7. Flooding Attack . . . . . . . . . . . . . . . . . . . . 26 14.8. Flooding Attack . . . . . . . . . . . . . . . . . . . . 26
10.8. Replay Attack . . . . . . . . . . . . . . . . . . . . . 27 14.9. Replay Attack . . . . . . . . . . . . . . . . . . . . . 27
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
12. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 28 16. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 28
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 17. Annex . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
13.1. Normative References . . . . . . . . . . . . . . . . . . 28 17.1. Envisioned deployment scenarios . . . . . . . . . . . . 28
13.2. Informative References . . . . . . . . . . . . . . . . . 31 17.1.1. CPE Vendor . . . . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 17.1.2. Agnostic CPE . . . . . . . . . . . . . . . . . . . . 29
17.2. Example: Homenet Zone . . . . . . . . . . . . . . . . . 29
17.3. Example: HNA necessary parameters for outsourcing . . . 31
18. References . . . . . . . . . . . . . . . . . . . . . . . . . 32
18.1. Normative References . . . . . . . . . . . . . . . . . . 33
18.2. Informative References . . . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
1. Requirements notation 1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Introduction 2. Introduction
IPv6 provides global end to end IP reachability. End users prefer to IPv6 provides global end to end IP connectivity. End users prefer to
use names instead of long and complex IPv6 addresses when accessing use names instead of long and complex IPv6 addresses when accessing
services hosted in the home network. services hosted in the home network.
Customer Edge Routers and other Customer Premises Equipment (CPEs) [RFC7368] recommends that home networks be resilient to connectivity
are already providing IPv6 connectivity to the home network, and disruption from the ISP. The public names should be resolvable
generally provide IPv6 addresses or prefixes to the nodes of the home within the home network and on the Internet, even when there are
network. In addition, [RFC7368] recommends that home networks be disruptions. This could be achieved by a device inside the home
resilient to connectivity disruption from the ISP. This could be network that builds, publishes, and manages a Public Homenet Zone,
achieved by a dedicated device inside the home network that builds, thus providing bindings between public names, IP addresses, and other
serves or manage the Homenet Zone, thus providing bindings between RR types.
names and IP addresses.
CPEs are of course good candidates to manage the binding between The management of the names can be a role that the Customer Premises
names and IP addresses of nodes. However, this could also be Equipment (CPE) does. Other devices in the home network could
performed by another device in the home network that is not a CPE. fulfill this role e.g. a NAS server, but for simplicity, this
In addition, a given home network may have multiple nodes that may document assumes the function is located on one of the CPE devices.
implement this functionality. Since management of the Homenet Zone
involves DNS specific mechanisms that cannot be distributed (primary
server), when multiple nodes can potentially manage the Homenet Zone,
a single node needs to be selected. This selected node is designated
as the Homenet Naming Authority (HNA).
CPEs, Homenet Naming Authority, as well as home network devices are A home network may have multiple CPEs. Since management of the
usually low powered devices not designed not for terminating heavy Public Homenet Zone involves DNS specific mechanisms that cannot be
traffic. As a result, hosting an authoritative DNS service on the distributed over multiple servers (primary server), when multiple
Internet may expose the home network to resource exhaustion and other nodes can potentially manage the Public Homenet Zone, a single node
attacks. This may isolate the home network from the Internet and needs to be selected per outsourced zone. This selected node is
also impact the services hosted by the such an home network device, designated as providing the Homenet Naming Authority (HNA) function.
thus affecting overall home network communication.
The process by which a single HNA is selected per zone is not in
scope for this document.
CPEs, which may host the HNA function, as well as home network
devices, are usually low powered devices not designed for terminating
heavy traffic. As a result, hosting an authoritative DNS service
visible to the Internet may expose the home network to resource
exhaustion and other attacks. Additionally, the names could become
unavailable during disruptions of the upstream Internet connectivity.
In order to avoid resource exhaustion and other attacks, this In order to avoid resource exhaustion and other attacks, this
document describes an architecture that outsources the authoritative document describes an architecture that outsources the authoritative
naming service of the home network. More specifically, the Homenet naming service of the home network. More specifically, the HNA
Naming Authority builds the Homenet Zone and outsources it to an builds the Public Homenet Zone and outsources it to an Outsourcing
Outsourcing Infrastructure. The Outsourcing Infrastructure in in Infrastructure via a Distribution Master (DM). The Outsourcing
charge of publishing the corresponding Public Homenet Zone on the Infrastructure is in charge of publishing the corresponding Public
Internet. Homenet Zone on the Internet. The transfer of DNS zone information
is achieved using standard DNS mechanisms involving primary and
secondary DNS servers, with the HNA hosted primary being a stealth
primary, and the Distribution Master a secondary.
Section 4.1 provides an architecture description that describes the Section 4.1 provides an architecture description that describes the
relation between the Homenet Naming Authority and the Outsourcing relation between the HNA and the Outsourcing Architecture. In order
Architecture. In order to keep the Public Homenet Zone up-to-date to keep the Public Homenet Zone up-to-date Section 6 describes how
Section 5 describes how the Homenet Zone and the Public Homenet Zone the HNA and the Outsourcing Infrastructure synchronizes the Pubic
can be synchronized. The proposed architecture aims at deploying Homenet Zone.
DNSSEC, and the Public Homenet Zone is expected to be signed with a
secure delegation. The zone signing and secure delegation may be The proposed architecture is explicitly designed to enable fully
performed either by the Homenet Naming Authority or by the functional DNSSEC, and the Public Homenet Zone is expected to be
Outsourcing Infrastructure. Section 6 discusses these two signed with a secure delegation. DNSSEC key management and zone
alternatives. Section 7 discusses the consequences of publishing signing is handled by the HNA.
multiple representations of the same zone also commonly designated as
views. This section provides guidance to limit the risks associated Section 10 discusses management of one or more reverse zones.
with multiple views. Section 7.4 discusses management of the reverse Section 11 discusses how renumbering should be handled. Finally,
zone. Section 8 discusses how renumbering should be handled. Section 13 and Section 14 respectively discuss privacy and security
Finally, Section 9 and Section 10 respectively discuss privacy and considerations when outsourcing the Public Homenet Zone.
security considerations when outsourcing the Homenet Zone.
The Public Homenet Zone is expected to contain public information
only in a single universal view. This document does not define how
the information required to construct this view is derived.
It is also not in the scope of this document to define names for
exclusive use within the boundaries of the local home network.
Instead, local scope information is expected to be provided to the
home network using local scope naming services. mDNS [RFC6762] DNS-SD
[RFC6763] are two examples of these services. Currently mDNS is
limited to a single link network. However, future protocols and
architectures [I-D.ietf-homenet-simple-naming] are expected to
leverage this constraint as pointed out in [RFC7558].
2.1. Alternative solutions
An alternative existing solution in IPv4 is to have a single zone,
where a host uses a RESTful HTTP service to register a single name
into a common public zone. This is often called "Dynamic DNS", and
there are a number of commercial providers, including Dyn, Gandi etc.
These solutions were typically used by a host behind the CPE to make
it's CPE IPv4 address visible, usually in order to enable incoming
connections.
For a small number (one to three) of hosts, use of such a system
provides an alternative to the architecture described in this
document.
The alternative does suffer from some severe limitations:
o the CPE/HNA router is unaware of the process, and cannot respond
to queries for these names when there are disruptions in
connectivity. This makes the home user or application dependent
on having to resolve different names in the event of outages or
disruptions.
o the CPE/HNA router cannot control the process. Any host can do
this regardless of whether or not the home network administrator
wants the name published or not. There is therefore no possible
audit trail.
o the credentials for the dynamic DNS server need to be securely
transferred to all hosts that wish to use it. This is not a
problem for a technical user to do with one or two hosts, but it
does not scale to multiple hosts and becomes a problem for non-
technical users.
o "all the good names are taken" - current services put everyone's
names into some small set of zones, and there are often conflicts.
Distinguishing similar names by delegation of zones was among the
primary design goals of the DNS system.
o The RESTful services do not always support all RR types. The
homenet user is dependent on the service provider supporting new
types. By providing full DNS delegation, this document enables
all RR types and also future extensions.
There is no technical reason why a RESTful cloud service could not
provide solutions to many of these problems, but this document
describes a DNS based solution.
3. Terminology 3. Terminology
o Customer Premises Equipment: (CPE) is a router providing o Customer Premises Equipment: (CPE) is a router providing
connectivity to the home network. connectivity to the home network.
o Homenet Naming Authority: (HNA) is a home network node responsible o Homenet Zone: is the DNS zone for use within the boundaries of the
to manage the Homenet Zone. This includes building the Homenet home network: home.arpa, see [RFC8375]). This zone is not
Zone, as well as managing the distribution of that Homenet Zone considered public and is out of scope for this document.
through the Outsourcing Infrastructure.
o Registered Homenet Domain: is the Domain Name associated to the o Registered Homenet Domain: is the Domain Name associated with the
home network. home network.
o Homenet Zone: is the DNS zone associated with the home network. o Public Homenet Zone: contains the names in the home network that
It is designated by its Registered Homenet Domain. This zone is are expected to be publicly resolvable on the Internet.
built by the HNA and contains the bindings between names and IP
addresses of the nodes in the home network. The HNA synchronizes
the Homenet Zone with the Synchronization Server via a hidden
primary / secondary architecture. The Outsourcing Infrastructure
may process the Homenet Zone - for example providing DNSSEC
signing - to generate the Public Homenet Zone. This Public
Homenet Zone is then transmitted to the Public Authoritative
Server(s) that publish it on the Internet.
o Public Homenet Zone: is the public version of the Homenet Zone. o Homenet Naming Authority: (HNA) is a function responsible for
It is expected to be signed with DNSSEC. It is hosted by the managing the Public Homenet Zone. This includes populating the
Public Authoritative Server(s), which are authoritative for this Public Homenet Zone, signing the zone for DNSSEC, as well as
zone. The Public Homenet Zone and the Homenet Zone might be managing the distribution of that Homenet Zone to the Outsourcing
different. For example some names might not become reachable from Infrastructure.
the Internet, and thus not be hosted in the Public Homenet Zone.
Another example of difference may also occur when the Public
Homenet Zone is signed whereas the Homenet Zone is not signed.
o Outsourcing Infrastructure: is the combination of the o Outsourcing Infrastructure: is the infrastructure responsible for
Synchronization Server and the Public Authoritative Server(s). receiving the Public Homenet Zone and publishing it on the
Internet. It is mainly composed of a Distribution Master and
Public Authoritative Servers.
o Public Authoritative Servers: are the authoritative name servers o Public Authoritative Servers: are the authoritative name servers
hosting the Public Homenet Zone. Name resolution requests for the for the Public Homenet Zone. Name resolution requests for the
Homenet Domain are sent to these servers. For resiliency the Homenet Domain are sent to these servers. For resiliency the
Public Homenet Zone SHOULD be hosted on multiple servers. Public Homenet Zone SHOULD be hosted on multiple servers.
o Synchronization Server: is the server with which the HNA o Homenet Authoritative Servers: are authoritative name servers
synchronizes the Homenet Zone. The Synchronization Server is within the Homenet network.
configured as a secondary and the HNA acts as primary. There MAY
be multiple Synchronization Servers, but the text assumes a single o Distribution Master (DM): is the (set of) server(s) to which the
server. In addition, the text assumes the Synchronization Server HNA synchronizes the Public Homenet Zone, and which then
is a separate entity. This is not a requirement, and when the HNA distributes the relevant information to the Public Authoritative
signs the zone, the synchronization function might also be Servers.
operated by the Public Authoritative Servers.
o Homenet Reverse Zone: The reverse zone file associated with the o Homenet Reverse Zone: The reverse zone file associated with the
Homenet Zone. Public Homenet Zone.
o Reverse Public Authoritative Servers: are the authoritative name o Reverse Public Authoritative Servers: equivalent to Public
server(s) hosting the Public Homenet Reverse Zone. Queries for Authoritative Servers specifically for reverse resolution.
reverse resolution of the Homenet Domain are sent to this server.
Similarly to Public Authoritative Servers, for resiliency, the
Homenet Reverse Zone SHOULD be hosted on multiple servers.
o Reverse Synchronization Server: is the server with which the HNA o Reverse Distribution Master: equivalent to Distribution Master
synchronizes the Homenet Reverse Zone. It is configured as a specifically for reverse resolution.
secondary and the HNA acts as primary. There MAY be multiple
Reverse Synchronization Servers, but the text assumes a single
server. In addition, the text assumes the Reverse Synchronization
Server is a separate entity. This is not a requirement, and when
the HNA signs the zone, the synchronization function might also be
operated by the Reverse Public Authoritative Servers.
o Hidden Primary: designates the primary server of the HNA, that o Homenet DNSSEC Resolver: a resolver that performs a DNSSEC
synchronizes the Homenet Zone with the Synchronization Server. A resolution on the home network for the Public Homenet Zone. The
primary / secondary architecture is used between the HNA and the resolution is performed requesting the Homenet Authoritative
Synchronization Server. The hidden primary is not expected to Servers.
serve end user queries for the Homenet Zone as a regular primary
server would. The hidden primary is only known to its associated o DNSSEC Resolver: a resolver that performs a DNSSEC resolution on
Synchronization Server. the Internet for the Public Homenet Zone. The resolution is
performed requesting the Public Authoritative Servers.
4. Architecture Description 4. Architecture Description
Architecture Description This section describes the architecture for This section provides an overview of the architecture for outsourcing
outsourcing the authoritative naming service from the HNA to the the authoritative naming service from the HNA to the Outsourcing
Outsourcing Infrastructure. Section 4.1 describes the architecture, Infrastructure in Section 4.1. Section Section 17.2 and Section 17.3
Section 4.2 and Section 4.3 illustrates this architecture and shows illustrates this architecture with the example of a Public Homenet
how the Homenet Zone should be built by the HNA. It also lists the Zone as well as necessary parameter to configure the HNA.
necessary parameters the HNA needs to be able to outsource the
authoritative naming service. These two sections are informational
and non-normative.
4.1. Architecture Overview 4.1. Architecture Overview
Figure 1 provides an overview of the architecture. Figure Figure 1 illustrates the architecture where the HNA outsources
the publication of the Public Homenet Zone to the Outsourcing
Infrastructure.
The home network is designated by the Registered Homenet Domain Name The Public Homenet Zone is identified by the Registered Homenet
- example.com in Figure 1. The HNA builds the Homenet Zone Domain Name - example.com.
associated with the home network. How the Homenet Zone is built is
out of the scope of this document. The HNA may host or interact with
multiple services to determine name-to-address mappings, such as a
web GUI, DHCP [RFC6644] or mDNS [RFC6762]. These services may
coexist and may be used to populate the Homenet Zone. This document
assumes the Homenet Zone has been populated with domain names that
are intended to be publicly published and that are publicly
reachable. More specifically, names associated with services or
devices that are not expected to be reachable from outside the home
network or names bound to non-globally reachable IP addresses MUST
NOT be part of the Homenet Zone.
Once the Homenet Zone has been built, the HNA does not host an ".local" as well as ".home.arpa" are explicitly not considered as
authoritative naming service, but instead outsources it to the Public Homenet zones.
Outsourcing Infrastructure. The Outsourcing Infrastructure takes the
Homenet Zone as an input and publishes the Public Homenet Zone. If
the HNA does not sign the Homenet Zone, the Outsourcing
Infrastructure may instead sign it on behalf of the HNA. Figure 1
provides a more detailed description of the Outsourcing
Infrastructure, but overall, it is expected that the HNA provides the
Homenet Zone. Then the Public Homenet Zone is derived from the
Homenet Zone and published on the Internet.
As a result, DNS queries from the DNS resolvers on the Internet are The HNA SHOULD build the Public Homenet Zone in a single view
answered by the Outsourcing Infrastructure and do not reach the HNA. populated with all resource records that are expected to be published
Figure 1 illustrates the case of the resolution of node1.example.com. on the Internet.
home network +-------------------+ Internet Resource records associated with services or devices that are not
| | expected to be resolvable from outside the home network, or resource
| HNA | records bound to non-globally reachable IP addresses e.g. ULA, MUST
| | +-----------------------+ NOT be part of the Public Homenet Zone.
+-------+ |+-----------------+| | Public Authoritative |
| | || Homenet Zone || | Server(s) |
| node1 | || || |+---------------------+|
| | || || || Public Homenet Zone ||
+-------+ || Homenet Domain ||=========|| ||
|| Name || ^ || (example.com) ||
node1.\ || (example.com) || | |+---------------------+|
example.com |+-----------------+| | +-----------------------+
+-------------------+ | ^ |
Synchronization | |
| |
DNSSEC resolution for node1.example.com | v
+-----------------------+
| |
| DNSSEC Resolver |
| |
+-----------------------+
Figure 1: Homenet Naming Architecture Description How the Public Homenet Zone is populated is out of the scope of this
document. The node providing the HNA function may also host or
interact with multiple services to determine name-to-address
mappings, such as a web GUI, DHCP [RFC6644] or mDNS [RFC6762]. These
services may coexist and may be used to populate the Public Homenet
Zone.
The Outsourcing Infrastructure is described in Figure 2. The The HNA also signs the Public Homenet Zone. The HNA handles all
Synchronization Server receives the Homenet Zone as an input. The operations and keying material required for DNSSEC, so there is no
received zone may be transformed to output the Public Homenet Zone. provision made in this architecture for transferring private DNSSEC
Various operations may be performed here, however this document only related keying material between the HNA and the DM.
considers zone signing as a potential operation. This should occur
only when the HNA outsources this operation to the Synchronization
Server. On the other hand, if the HNA signs the Homenet Zone itself,
the zone would be collected by the Synchronization Server and
directly transferred to the Public Authoritative Server(s). These
policies are discussed and detailed in Section 6 and Section 7.
Internet Once the Public Homenet Zone has been built, the HNA outsources it to
the Outsourcing Infrastructure as described in Figure 1.
+------------------------------------------------------+ The HNA acts as a hidden primary while the DM behaves as a secondary
| Outsourcing Infrastructure | responsible to distribute the Public Homenet Zone to the multiple
+------------------------------------------------------+ Public Authoritative Servers that Outsourcing Infrastructure is
responsible for.
+----------------------+ +----------------------+ The DM has 3 communication channels: * a DM Control Channel (see
| | | | section Section 5) to configure the HNA and the Outsourcing
| Synchronization | | Public Authoritative | Infrastructure, * a DM Synchronization Channel (see section Section 6
| Server | | Server(s) | to synchronize the Public Homenet Zone on the HNA and on the DM. *
| | | | one or more Distribution Channels (see section Section 7 that
| +------------------+ | X |+--------------------+| distributes the Public Homenet Zone from the DM to the Public
| | Homenet Zone | | ^ || Public Homenet Zone|| Authoritative Server serving the Public Homenet Zone on the Internet.
=========>| | | | || ||
^ | | | | | || ||
| | | (example.com) | | | || (example.com) ||
| | +------------------+ | | |+--------------------+|
| +----------------------+ | +----------------------+
| Homenet to Public Zone
Synchronization transformation
from the HNA
Figure 2: Outsourcing Infrastructure Description There MAY be multiple DM's, and multiple servers per DM. This text
assumes a single DM server for simplicity, but there is no reason why
each channel need to be implemented on the same server, or indeed use
the same code base.
4.2. Example: Homenet Zone It is important to note that while the HNA is configured as an
authoritative server, it is not expected to answer to DNS requests
from the public Internet for the Public Homenet Zone. The function
of the HNA is limited to building the zone and synchronization with
the DM.
This section is not normative and intends to illustrate how the HNA The addresses associated with the HNA SHOULD NOT be mentioned in the
builds the Homenet Zone. NS records of the Public Homenet zone, unless additional security
provisions necessary to protect the HNA from external attack have
been taken.
As depicted in Figure 1 and Figure 2, the Public Homenet Zone is The Outsourcing Infrastructure is also responsible for ensuring the
hosted on the Public Authoritative Server(s), whereas the Homenet DS record has been updated in the parent zone.
Zone is hosted on the HNA. Motivations for keeping these two zones
identical are detailed in Section 7, and this section considers that
the HNA builds the zone that will be effectively published on the
Public Authoritative Server(s). In other words "Homenet to Public
Zone transformation" is the identity also commonly designated as "no
operation" (NOP).
In that case, the Homenet Zone should configure its Name Server RRset Resolution is performed by the DNSSEC resolvers. When the resolution
(NS) and Start of Authority (SOA) with the values associated with the is performed outside the home network, the DNSSEC Resolver resolves
Public Authoritative Server(s). This is illustrated in Figure 3. the DS record on the Global DNS and the name associated to the Public
public.primary.example.net is the FQDN of the Public Authoritative Homenet Zone (example.com) on the Public Authoritative Servers.
Server(s), and IP1, IP2, IP3, IP4 are the associated IP addresses.
Then the HNA should add the additional new nodes that enter the home
network, remove those that should be removed, and sign the Homenet
Zone.
$ORIGIN example.com When the resolution is performed from within the home network, the
$TTL 1h Homenet DNSSEC Resolver may proceed similarly. On the other hand, to
provide resilience to the Public Homenet Zone in case of disruption,
the Homenet DNSSEC Resolver SHOULD be able to perform the resolution
on the authoritative name service of the home network implemented by
the Homenet Authoritative Servers. These servers are not expected to
be mentioned in the Public Homenet Zone, nor to be accessible from
the Internet. As such their information as well as the corresponding
signed DS record MAY be provided by the HNA to the Homenet DNSSEC
Resolvers e.g. using HNCP. Such configuration is outside the scope
of this document.
@ IN SOA public.primary.example.net How the Homenet Authoritative Servers are provisioned is also out of
hostmaster.example.com. ( scope of this specification. It could be implemented using primary
2013120710 ; serial number of this zone file secondaries servers, or via rsync. In some cases, the HNA and
1d ; secondary refresh Homenet Authoritative Servers may be combined together which would
2h ; secondary retry time in case of a problem result in a common instantiation of an authoritative server on the
4w ; secondary expiration time WAN and inner interface. Other mechanisms may also be used.
1h ; maximum caching time in case of failed
; lookups
)
@ NS public.authoritative.servers.example.net Home network | Internet
|
| +----------------------------+
| | Outsourcing Infrastructure |
Control | | |
+-----------------------+Channel | | +-----------------------+ |
| HNA |<-------------->| Distribution Master | |
|+---------------------+| | | |+---------------------+| |
|| Public Homenet Zone ||Synchronization || Public Homenet Zone || |
|| (example.com) ||Channel | | || (example.com) || |
|+---------------------+|<-------------->|+---------------------+| |
+----------------------+| | | +-----------------------+ |
| | ^ Distribution |
| | | Channel |
+-----------------------+ | | v |
| Homenet Authoritative | | | +-----------------------+ |
| Server(s) | | | | Public Authoritative | |
|+---------------------+| | | | Server(s) | |
||Public Homenet Zone || | | |+---------------------+| |
|| (example.com) || | | || Public Homenet Zone || |
|+---------------------+| | | || (example.com) || |
+-----------------------+ | | |+---------------------+| |
^ | | | +-----------------------+ |
| | | +----------^---|-------------+
| | | | |
| | name resolution | |
| v | | v
+----------------------+ | +-----------------------+
| Homenet | | | Internet |
| DNSSEC Resolver | | | DNSSEC Resolver |
+----------------------+ | +-----------------------+
public.primary.example.net A @IP1 Figure 1: Homenet Naming Architecture Name Resolution
public.primary.example.net A @IP2
public.primary.example.net AAAA @IP3
public.primary.example.net AAAA @IP4
Figure 3: Homenet Zone 4.2. Distribution Master Communication Channels
The SOA RRset is defined in [RFC1033], [RFC1035] and [RFC2308]. This This section details the interfaces and channels of the DM, that is
SOA is specific, as it is used for the synchronization between the the Control Channel, the Synchronization Channel and the Distribution
Hidden Primary and the Synchronization Server and published on the Channel.
DNS Public Authoritative Server(s)..
o MNAME: indicates the primary. In our case the zone is published The Control Channel and the Synchronization Channel are the
on the Public Authoritative Server(s), and its name MUST be interfaces used between the HNA and the Outsourcing Infrastructure.
included. If multiple Public Authoritative Server(s) are The entity within the Outsourcing Infrastructure responsible to
involved, one of them MUST be chosen. More specifically, the HNA handle these communications is the DM and communications between the
MUST NOT include the name of the Hidden Primary. HNA and the DM SHOULD be protected and mutually authenticated. While
section Section 5.6 discusses in more depth the different security
protocols that could be used to secure, this specification RECOMMENDS
the use of TLS with mutually authentication based on certificates to
secure the channel between the HNA and the DM.
o RNAME: indicates the email address to reach the administrator. The Control Channel is used to set up the Synchronization Channel.
[RFC2142] recommends using hostmaster@domain and replacing the '@' We assume that the HNA initiates the Control Channel connection with
sign by '.'. the DM and as such has a prior knowledge of the DM identity (X509
certificate), the IP address and port to use and protocol to set
secure session. We also assume the DM has knowledge of the identity
of the HNA (X509 certificate) as well as the Registered Homenet
Domain.
o REFRESH and RETRY: indicate respectively in seconds how often The information exchanged between the HNA and the DM is using DNS
secondaries need to check the primary, and the time between two messages. DNS messages can be protected using various kind of
refresh when a refresh has failed. Default values indicated by transport layers, among others, UDP:53/DTLS, TLS/TCP:53, HTTPS:443.
[RFC1033] are 3600 (1 hour) for refresh and 600 (10 minutes) for There was consideration to using a standard TSIG [RFC2845] or SIG(0)
retry. This value might be too long for highly dynamic content. [RFC2931] to perform a dynamic DNS update to the DM. There are a
However, the Public Authoritative Server(s) and the HNA are number of issues with this. The main one is that the Dynamic DNS
expected to implement NOTIFY [RFC1996]. So whilst shorter refresh update would also update the zone's NS records, while the goal is to
timers might increase the bandwidth usage for secondaries hosting update the Distribution Master's configuration files. The visible NS
large number of zones, it will have little practical impact on the records SHOULD remain pointing at the cloud provider's anycast
elapsed time required to achieve synchronization between the addresses. Revealing the address of the HNA in the DNS is not
Outsourcing Infrastructure and the Hidden Master. As a result, desireable.
the default values are acceptable.
o EXPIRE: is the upper limit data SHOULD be kept in absence of This specification also assumes the same transport protocol and ports
refresh. The default value indicated by [RFC1033] is 3600000 used by the DM to serve the Control Channel and by the HNA to serve
(approx. 42 days). In home network architectures, the HNA the Synchronization Channel are the same.
provides both the DNS synchronization and the access to the home
network. This device may be plugged and unplugged by the end user
without notification, thus we recommend a long expiry timer.
o MINIMUM: indicates the minimum TTL. The default value indicated The Distribution Channel is internal to the Outsourcing
by [RFC1033] is 86400 (1 day). For home network, this value MAY Infrastructure and as such is not the primary concern of this
be reduced, and 3600 (1 hour) seems more appropriate. specification.
<<!-- ## Considerations on multiple Registered Homenet Domain Names 5. Control Channel between HNA and DM
## are left for future versions When multiple Registered Homenet
Domains are used -like example.com, example.net, example.org, a DNS
Homenet Zone file per Registered Homenet Domain SHOULD be generated.
In order to synchronize the zone contents, the HNA may provide all
bindings in each zone files. As a result, any update MUST be
performed on all zone files, i.e. for all Registered Homenet Domains.
To limit thees updates when multiple Registered Homenet Domains are
involved, the HNA MAY fill all bindings in a specific zone file and
redirect all other zones to that zone. This can be achieved with
redirecting mechanisms like CNAME {{RFC2181}}, {{RFC1034}}, DNAME
{{RFC6672}} or CNAME+DNAME {{I-D.sury-dnsext-cname-dname}}. This is
an implementation issue to determine whether redirection mechanisms
MAY be preferred for large Homenet Zones, or when the number of
Registered Homenet Domain becomes quite large. -->>
4.3. Example: HNA necessary parameters for outsourcing The DM Control Channel is used by the HNA and the Outsourcing
Infrastructure to exchange information related to the configuration
of the delegation which includes:
This section specifies the various parameters required by the HNA to 5.1. Information to build the Public Homenet Zone.
configure the naming architecture of this document. This section is
informational, and is intended to clarify the information handled by
the HNA and the various settings to be done.
Synchronization Server may be configured with the following More specifically, the Public Homenet Zone contains information that
parameters. These parameters are necessary to establish a secure is related to the infrastructure serving the zone. In our case, the
channel between the HNA and the Synchronization Server as well as to infrastructure serving the Public Homenet Zone is the Outsourcing
specify the DNS zone that is in the scope of the communication: Infrastructure, so this information MUST reflect that Outsourcing
Infrastructure and MUST be provided to the HNA.
o Synchronization Server: The associated FQDNs or IP addresses of The information includes at least names and IP addresses of the
the Synchronization Server. IP addresses are optional and the Public Authoritative Servers. In term of RRset information this
FQDN is sufficient. To secure the binding name and IP addresses, corresponds, for the Registered Homenet Domain the MNAME of the SOA,
a DNSSEC exchange is required. Otherwise, the IP addresses should the NS and associated A and AAA RRsets. Optionally the Outsourcing
be entered manually. Infrastructure MAY also provide operational parameters such as other
fields of SOA (SERIAL, RNAME, REFRESH, RETRY, EXPIRE and MINIMUM).
As the information is necessary for the HNA to proceed and the
information is associated to the Outsourcing Infrastructure, this
information exchange is mandatory.
o Authentication Method: How the HNA authenticates itself to the 5.2. Information to build the DNSSEC chain of trust.
Synchronization Server. This MAY depend on the implementation but
this should cover at least IPsec, DTLS and TSIG
o Authentication data: Associated Data. PSK only requires a single The HNA SHOULD provide the hash of the KSK (DS RRset), so the that
argument. If other authentication mechanisms based on Outsourcing Infrastructure provides this value to the parent zone. A
certificates are used, then HNA private keys, certificates and common deployment use case is that the Outsourcing Infrastructure is
certification authority should be specified. 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 Outsourcing Infrastructure to update the DS RRset
in the parent zone. A direct update is especially necessary to
initialize the chain of trust.
o Public Authoritative Server(s): The FQDN or IP addresses of the Though the HNA may also later directly update the values of the DS
Public Authoritative Server(s). It MAY correspond to the data via the Control Channel, it is RECOMMENDED to use other mechanisms
that will be set in the NS RRsets and SOA of the Homenet Zone. IP such as CDS and CDNSKEY [RFC7344] are used for key roll overs.
addresses are optional and the FQDN is sufficient. To secure the
binding between name and IP addresses, a DNSSEC exchange is
required. Otherwise, the IP addresses should be entered manually.
o Registered Homenet Domain: The domain name used to establish the As some deployment may not provide an Outsourcing Infrastructure that
secure channel. This name is used by the Synchronization Server will be able to update the DS in the parent zone, this information
and the HNA for the primary / secondary configuration as well as exchange is OPTIONAL.
to index the NOTIFY queries of the HNA when the HNA has been
renumbered.
Setting the Homenet Zone requires the following information. By accepting the DS, the DM commits in taking care of advertising the
DS to the parent zone. Upon refusal, the DM MUST clearly indicate
the DM does not have the capacity to proceed to the update.
o Registered Homenet Domain: The Domain Name of the zone. Multiple 5.3. Information to set the Synchronization Channel,
Registered Homenet Domains may be provided. This will generate
the creation of multiple Public Homenet Zones.
o Public Authoritative Server(s): The Public Authoritative Server(s) That information sets the primary/secondary relation between the HNA
associated with the Registered Homenet Domain. Multiple Public and the DM. The HNA works as a primary authoritative DNS server, and
Authoritative Server(s) may be provided. MUST provide the corresponding IP address.
5. Synchronization between HNA and the Synchronization Server The specified IP address on the HNA side and the currently used IP
address of the DM defines the IP addresses involved in the
Synchronization Channel. Ports and transport protocol are the same
as those used by the Control Channel. By default, the same IP
address used by the HNA is considered by the DM. Exchange of this
information is OPTIONAL.
The Homenet Reverse Zone and the Homenet Zone MAY be updated either 5.4. Deleting the delegation
with DNS UPDATE [RFC2136] or using a primary / secondary
synchronization. The primary / secondary mechanism is preferred as
it scales better and avoids DoS attacks: First the primary notifies
the secondary that the zone must be updated and leaves the secondary
to proceed with the update when possible. Then, a NOTIFY message is
sent by the primary, which is a small packet that is less likely to
load the secondary. Finally, the AXFR query performed by the
secondary is a small packet sent over TCP (section 4.2 [RFC5936]),
which mitigates reflection attacks using a forged NOTIFY. On the
other hand, DNS UPDATE (which can be transported over UDP), requires
more processing than a NOTIFY, and does not allow the server to
perform asynchronous updates.
This document RECOMMENDS use of a primary / secondary mechanism The purpose of the previous sections were to exchange information in
instead of the use of DNS UPDATE. This section details the primary / order to set a delegation. The HNA MUST also be able to delete a
secondary mechanism. delegation with a specific DM. Upon an instruction of deleting the
delegation, the DM MUST stop serving the Public Homenet Zone.
5.1. Synchronization with a Hidden Primary 5.5. Messages Exchange Description
Uploading and dynamically updating the zone file on the There are multiple ways these information could be exchanged between
Synchronization Server can be seen as zone provisioning between the the HNA and the DM. This specification defines a mechanism that re-
HNA (Hidden Primary) and the Synchronization Server (Secondary use the DNS exchanges format. The intention is to reuse standard
Server). This can be handled either in band or out of band. libraries especially to check the format of the exchanged fields as
well as to minimize the additional libraries needed for the HNA. The
re-use of DNS exchanges achieves these goals. Note that while
information is provided using DNS exchanges, the exchanged
information is not expected to be set in any zone file, instead this
information is expected to be processed appropriately.
Note that there is no standard way to distribute a DNS primary The Control Channel is not expected to be a long term session. After
between multiple devices. As a result, if multiple devices are a predefined timer the Control Channel is expected to be terminated.
candidate for hosting the Hidden Primary, some specific mechanisms The Control Channel MAY Be re-opened at any time later.
should be designed so the home network only selects a single HNA for
the Hidden Primary. Selection mechanisms based on HNCP [RFC7788] are
good candidates.
The Synchronization Server is configured as a secondary for the The provisioning process SHOULD provide a method of securing the
Homenet Domain Name. This secondary configuration has been control channel, so that the content of messages can be
previously agreed between the end user and the provider of the authenticated. This authentication MAY be based on certificates for
Synchronization Server. In order to set the primary / secondary both the DM and each HNA. The DM may also create the initial
architecture, the HNA acts as a Hidden Primary Server, which is a configuration for the delegation zone in the parent zone during the
regular authoritative DNS Server listening on the WAN interface. provisioning process.
The Hidden Primary Server SHOULD accept SOA [RFC1033], AXFR 5.5.1. Retrieving information for the Public Homenet Zone.
[RFC1034], and IXFR [RFC1995] queries from its configured secondary
DNS server(s). The Hidden Primary Server SHOULD send NOTIFY messages
[RFC1996] in order to update Public DNS server zones as updates
occur. Because, the Homenet Zones are likely to be small, the HNA
MUST implement AXFR and SHOULD implement IXFR.
Hidden Primary Server differs from a regular authoritative server for The information provided by the DM to the HNA is retrieved by the HNA
the home network by: with a AXFR exchange. The AXFR message enables the response to
contain any type of RRsets. The response might be extended in the
future if additional information will be needed. Alternatively, the
information provided by the HNA to the DM is pushed by the HNA via a
DNS update exchange.
o Interface Binding: the Hidden Primary Server listens on the WAN To retrieve the necessary information to build the Public Homenet
Interface, whereas a regular authoritative server for the home Zone, the HNA MUST send an DNS request of type AXFR associated to the
network would listen on the home network interface. Registered Homenet Domain. The DM MUST respond with a zone template.
The zone template MUST contain a RRset of type SOA, one or multiple
RRset of type NS and at least one RRset of type A or AAAA. The SOA
RR is used to indicate 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 Outsourcing Infrastructure to the HNA. Other RDATA
values (RNAME, REFRESH, RETRY, EXPIRE and MINIMUM) are provided by
the Outsourcing Infrastructure as suggestions. The NS RRsets are
used to carry the Public Authoritative Servers of the Outsourcing
Infrastructure. Their associated NAME MUST be the Registered Homenet
Domain. The TTL and RDATA are those expected to be published on the
Public Homenet Zone. The RRsets of Type A and AAAA MUST have their
NAME matching the NSDNAME of one of the NS RRsets.
o Limited exchanges: the purpose of the Hidden Primary Server is to Upon receiving the response, the HNA MUST validate the conditions on
synchronize with the Synchronization Server, not to serve any the SOA, NS and A or AAAA RRsets. If an error occurs, the HNA MUST
zones to end users. As a result, exchanges are performed with stop proceeding and MUST report an error. Otherwise, the HNA builds
specific nodes (the Synchronization Server). Further, exchange the Public Homenet Zone by setting the MNAME value of the SOA as
types are limited. The only legitimate exchanges are: NOTIFY indicated by the SOA provided by the AXFR response. The HNA SHOULD
initiated by the Hidden Primary and IXFR or AXFR exchanges set the value of NAME, REFRESH, RETRY, EXPIRE and MINIMUM of the SOA
initiated by the Synchronization Server. On the other hand, to those provided by the AXFR response. The HNA MUST insert the NS
regular authoritative servers would respond to any hosts, and any and corresponding A or AAAA RRset in its Public Homenet Zone. The
DNS query would be processed. The HNA SHOULD filter IXFR/AXFR HNA MUST ignore other RRsets. If an error message is returned by the
traffic and drop traffic not initiated by the Synchronization DM, the HNA MUST proceed as a regular DNS resolution. Error messages
Server. The HNA MUST listen for DNS on TCP and UDP and MUST at SHOULD be logged for further analysis. If the resolution does not
least allow SOA lookups of the Homenet Zone. succeed, the outsourcing operation is aborted and the HNA MUST close
the Control Channel.
5.2. Securing Synchronization 5.5.2. Providing information for the DNSSEC chain of trust
Exchange between the Synchronization Server and the HNA MUST be To provide the DS RRset to initialize the DNSSEC chain of trust the
secured, at least for integrity protection and for authentication. HNA MAY send a DNS UPDATE [RFC2136] message. The NAME in the SOA
MUST be set to the parent zone of the Registered Homenet Domain -
that is where the DS records should be inserted. The DS RRset MUST
be placed in the Update section of the UPDATE query, and the NAME
SHOULD be set to the Registered Homenet Domain. The rdata of the DS
RR SHOULD correspond to the DS record to be inserted in the parent
zone.
TSIG [RFC2845] or SIG(0) [RFC2931] MAY be used to secure the DNS A NOERROR response from the MD is a commitment to update the parent
communications between the HNA and the Synchronization Server. TSIG zone with the provided DS. An error indicates the MD will not update
uses a symmetric key which can be managed by TKEY [RFC2930]. the DS, and other method should be used by the HNA.
Management of the key involved in SIG(0) is performed through zone
updates. How keys are rolled over with SIG(0) is out-of-scope of
this document. The advantage of these mechanisms is that they are
only associated with the DNS application. Not relying on shared
libraries eases testing and integration. On the other hand, using
TSIG, TKEY or SIG(0) requires these mechanisms to be implemented on
the HNA, which adds code and complexity. Another disadvantage is
that TKEY does not provide authentication mechanisms.
Protocols like TLS [RFC5246] / DTLS [RFC6347] MAY be used to secure 5.5.3. Providing information for the Synchronization Channel
the transactions between the Synchronization Server and the HNA. The
advantage of TLS/DTLS is that this technology is widely deployed, and
most of the devices already embed TLS/DTLS libraries, possibly also
taking advantage of hardware acceleration. Further, TLS/DTLS
provides authentication facilities and can use certificates to
authenticate the Synchronization Server and the HNA. On the other
hand, using TLS/DTLS requires implementing DNS exchanges over TLS/
DTLS, as well as a new service port. This document therefore does
NOT RECOMMEND this option.
IPsec [RFC4301] IKEv2 [RFC7296] MAY also be used to secure To provide the IP address of the primary, the HNA MAY send a DNS
transactions between the HNA and the Synchronization Server. UPDATE message. The NAME in the SOA MUST be the parent zone of the
Similarly to TLS/DTLS, most HNAs already embed an IPsec stack, and Registered Homenet Domain. The Update section MUST be a RRset of
IKEv2 supports multiple authentication mechanisms via the EAP Type NS. The NAME associated to the NS RRSet MUST be the Registered
framework. In addition, IPsec can be used to protect DNS exchanges Domain Name. The RDATA MUST be a FQDN that designates the IP
between the HNA and the Synchronization Server without any addresses associated to the primary. There may be multiple IP
modifications of the DNS server or client. DNS integration over addresses. These IP addresses MUST be provided in the additional
IPsec only requires an additional security policy in the Security section. The reason to provide these IP addresses is that it is NOT
Policy Database (SPD). One disadvantage of IPsec is that NATs and RECOMMENDED to publish these IP addresses. As a result, it is not
firewall traversal may be problematic. However, in our case, the HNA expected to resolve them. IP addresses are provided via RRsets of
is connected to the Internet, and IPsec communication between the HNA type A or AAAA. The NAME associated to RRsets of type A and AAAA
and the Synchronization Server should not be impacted by middle MUST be the Registered Homenet Domain.
boxes.
<<!-- As mentioned above, TSIG, IPsec and TLS/DTLS MAY be used to A NOERROR response indicates the DM has configured the secondary and
secure transactions between the HNA and the Public Authentication is committed to serve as a secondary. An error indicates the DM is
Servers. The HNA and the Synchronization Server SHOULD implement not configured as a secondary.
TSIG and IPsec. -->>
How the PSK can be used by any of the TSIG, TLS/DTLS or IPsec The regular DNS error message SHOULD be returned to the HNA when an
protocols: Authentication based on certificates implies a mutual error occurs. In particular a FORMERR is returned when a format
authentication and thus requires the HNA to manage a private key, a error is found, this error includes when unexpected RRSets are added
public key, or certificates, as well as Certificate Authorities. or when RRsets are missing. A SERVFAIL error is returned when a
This adds complexity to the configuration especially on the HNA side. internal error is encountered. a NOTZONE error is returned when
For this reason, we RECOMMEND that the HNA MAY use PSK or certificate update and Zone sections are not coherent, a NOTAUTH error is
base authentication, and that the Synchronization Server MUST support returned when the DM is not authoritative for the Zone section. A
PSK and certificate based authentication. REFUSED error is returned when the DM refuses to proceed to the
configuration and the requested action.
Note also that authentication of message exchanges between the HNA 5.5.4. HNA instructing deleting the delegation
and the Synchronization Server SHOULD NOT use the external IP address
of the HNA to index the appropriate keys. As detailed in Section 8,
the IP addresses of the Synchronization Server and the Hidden Primary
are subject to change, for example while the network is being
renumbered. This means that the necessary keys to authenticate
transaction SHOULD NOT be indexed using the IP address, and SHOULD be
resilient to IP address changes.
5.3. HNA Security Policies To instruct to delete the delegation the HNA MAY send a DNS UPDATE
Delete message. The NAME in the SOA MUST be the parent zone of the
Registered Homenet Domain. The Update section MUST be a RRset of
Type NS. The NAME associated to the NS RRSet MUST be the Registered
Domain Name. As indictaed 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.
This section details security policies related to the Hidden Primary 5.6. Securing the Control Channel between HNA and DM
/ Secondary synchronization.
The Hidden Primary, as described in this document SHOULD drop any The control channel between the HNA and the DM MUST be secured at
queries from the home network. This could be implemented via port both the HNA and the DM.
binding and/or firewall rules. The precise mechanism deployed is out
of scope of this document. The Hidden Primary SHOULD drop any DNS
queries arriving on the WAN interface that are not issued from the
Synchronization Server. The Hidden Primary SHOULD drop any outgoing
packets other than DNS NOTIFY query, SOA response, IXFR response or
AXFR responses. The Hidden Primary SHOULD drop any incoming packets
other than DNS NOTIFY response, SOA query, IXFR query or AXFR query.
The Hidden Primary SHOULD drop any non protected IXFR or AXFR
exchange,depending on how the synchronization is secured.
6. DNSSEC compliant Homenet Architecture Secure protocols (like TLS [RFC5246] / DTLS [RFC6347]) SHOULD be used
to secure the transactions between the DM and the HNA.
[RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on both The advantage of TLS/DTLS is that this technology is widely deployed,
the authoritative server and the resolver. The resolver side is out and most of the devices already embed TLS/DTLS libraries, possibly
of scope of this document, and only the authoritative part of the also taking advantage of hardware acceleration. Further, TLS/DTLS
server is considered. provides authentication facilities and can use certificates to
authenticate the DM and the HNA. On the other hand, using TLS/DTLS
requires implementing DNS exchanges over TLS/DTLS, as well as a new
service port. This document RECOMMENDS this option.
Deploying DNSSEC requires signing the zone and configuring a secure The HNA SHOULD authenticate inbound connections from the DM using
delegation. As described in Section 4.1, signing can be performed standard mechanisms, such as a public certificate with baked-in root
either by the HNA or by the Outsourcing Infrastructure. Section 6.1 certificates on the HNA, or via DANE {!RFC6698}}.
details the implications of these two alternatives. Similarly, the
secure delegation can be performed by the HNA or by the Outsourcing
Infrastructure. Section 6.2 discusses these two alternatives.
6.1. Zone Signing" The DM SHOULD authenticate the HNA and check that inbound messages
are from the appropriate client. The DM MAY use a self-signed CA
certificate mechanism per HNA, or public certificates for this
purpose.
This section discusses the pros and cons when zone signing is IPsec [RFC4301] IKEv2 [RFC7296] MAY also be used to secure
performed by the HNA or by the Outsourcing Infrastructure. It is transactions between the HNA and the DM. Similarly to TLS/DTLS, most
RECOMMENDED that the HNA signs the zone unless there is a strong HNAs already embed an IPsec stack, and IKEv2 supports multiple
argument against this, such as a HNA that is not capable of signing authentication mechanisms via the EAP framework. In addition, IPsec
the zone. In that case zone signing MAY be performed by the can be used to protect DNS exchanges between the HNA and the DM
Outsourcing Infrastructure on behalf of the HNA. without any modifications of the DNS server or client. DNS
integration over IPsec only requires an additional security policy in
the Security Policy Database (SPD). One disadvantage of IPsec is
that NATs and firewall traversal may be problematic. However, in our
case, the HNA is connected to the Internet, and IPsec communication
between the HNA and the DM should not be impacted by middle boxes.
Reasons for signing the zone by the HNA are: How the PSK can be used by any of the TSIG, TLS/DTLS or IPsec
protocols: Authentication based on certificates implies a mutual
authentication and thus requires the HNA to manage a private key, a
public key, or certificates, as well as Certificate Authorities.
This adds complexity to the configuration especially on the HNA side.
For this reason, we RECOMMEND that the HNA MAY use PSK or certificate
based authentication, and that the DM MUST support PSK and
certificate based authentication.
o 1) Keeping the Homenet Zone and the Public Homenet Zone equal to Note also that authentication of message exchanges between the HNA
securely optimize DNS resolution. As the Public Zone is signed and the DM SHOULD NOT use the external IP address of the HNA to index
with DNSSEC, RRsets are authenticated, and thus DNS responses can the appropriate keys. As detailed in Section 11, the IP addresses of
be validated even though they are not provided by the the DM and the Hidden Primary are subject to change, for example
authoritative server. This provides the HNA the ability to while the network is being renumbered. This means that the necessary
respond on behalf of the Public Authoritative Server(s). This keys to authenticate transaction SHOULD NOT be indexed using the IP
could be useful for example if, in the future, the HNA announces address, and SHOULD be resilient to IP address changes.
to the home network that the HNA can act as a local authoritative
primary or equivalent for the Homenet Zone. Currently the HNA is
not expected to receive authoritative DNS queries, as its IP
address is not mentioned in the Public Homenet Zone. On the other
hand most HNAs host a resolving function, and could be configured
to perform a local lookup to the Homenet Zone instead of
initiating a DNS exchange with the Public Authoritative Server(s).
Note that outsourcing the zone signing operation means that all
DNSSEC queries SHOULD be cached to perform a local lookup,
otherwise a resolution with the Public Authoritative Server(s)
would be performed.
o 2) Keeping the Homenet Zone and the Public Homenet Zone equal to 5.7. Implementation Tips
securely address the connectivity disruption independence detailed
in [RFC7368] section 4.4.1 and 3.7.5. As local lookups are
possible in case of network disruption, communications within the
home network can still rely on the DNSSEC service. Note that
outsourcing the zone signing operation does not address
connectivity disruption independence with DNSSEC. Instead local
lookup would provide DNS as opposed to DNSSEC responses provided
by the Public Authoritative Server(s).
o 3) Keeping the Homenet Zone and the Public Homenet Zone equal to The Hidden Primary Server on the HNA differs from a regular
guarantee coherence between DNS responses. Using a unique zone is authoritative server for the home network due to:
one way to guarantee uniqueness of the responses among servers and
places. Issues generated by different views are discussed in more
details in Section 7.
4) Privacy and Integrity of the DNSSEC Homenet Zone are better o Interface Binding: the Hidden Primary Server will almost certainly
guaranteed. When the Zone is signed by the HNA, it makes listen on the WAN Interface, whereas a regular authoritative
modification of the DNS data - for example for flow redirection - server for the home network would listen on the internal home
impossible. As a result, signing the Homenet Zone by the HNA network interface.
provides better protection for end user privacy.
Reasons for signing the zone by the Outsourcing Infrastructure are: o 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.
1) The HNA may not be capable of signing the zone, most likely As a result, exchanges are performed with specific nodes (the DM).
because its firmware does not support this function. However this Further, exchange types are limited. The only legitimate exchanges
reason is expected to become less and less valid over time. are: NOTIFY initiated by the Hidden Primary and IXFR or AXFR
exchanges initiated by the DM. On the other hand, regular
authoritative servers would respond to any hosts, and any DNS query
would be processed. The HNA SHOULD filter IXFR/AXFR traffic and drop
traffic not initiated by the DM. The HNA MUST listen for DNS on TCP
and UDP and MUST at least allow SOA lookups of the Homenet Zone.
2) Outsourcing DNSSEC management operations. Management operations 6. DM Synchronization Channel between HNA and DM
involve key roll-over, which can be performed automatically by the
HNA and transparently for the end user. Avoiding DNSSEC management
is mostly motivated by bad software implementations.
3) Reducing the impact of HNA replacement on the Public Homenet Zone. The DM Synchronization Channel is used for communication between the
Unless the HNA private keys can be extracted and stored off-device, HNA and the DM for synchronizing the Public Homenet Zone. Note that
HNA hardware replacement will result in an emergency key roll-over. the Control Channel and the Synchronization Channel are by
This can be mitigated by using relatively small TTLs. construction different channels even though there they MAY use the
same IP addresses. In fact the Control Channel is set between the
HNA working as a client using port YYYY (a high range port) toward a
service provided by the MD at port XX (well known port). On the
other hand, the Synchronization Channel is set between the MD working
as a client using port ZZZZ ( a high range port) toward a service a
service provided by the HNA at port XX. As a result, even though the
same couple of IP addresses may be involved the Control Channel and
the Synchronization Channel are always disc tint channels.
4) Reducing configuration impact on the end user. Unless there are Uploading and dynamically updating the zone file on the DM can be
zero configuration mechanisms in place to provide credentials between seen as zone provisioning between the HNA (Hidden Primary) and the DM
the new HNA and the Synchronization Server, authentication (Secondary Server). This can be handled via AXFR + DNS UPDATE.
associations between the HNA and the Synchronization Server would
need to be re-configured. As HNA replacement is not expected to
happen regularly, end users may not be at ease with such
configuration settings. However, mechanisms as described in
[I-D.ietf-homenet-naming-architecture-dhc-options] use DHCP Options
to outsource the configuration and avoid this issue.
5) The Outsourcing Infrastructure is more likely to handle private This document RECOMMENDS use of a primary / secondary mechanism
keys more securely than the HNA. However, having all private keys in instead of the use of DNS UPDATE. The primary / secondary mechanism
one place may also nullify that benefit. is RECOMMENDED as it scales better and avoids DoS attacks. Note that
even when UPDATE messages are used, these messages are using a
distinct channel as those used to set the configuration.
6.2. Secure Delegation" Note that there is no standard way to distribute a DNS primary
between multiple devices. As a result, if multiple devices are
candidate for hosting the Hidden Primary, some specific mechanisms
should be designed so the home network only selects a single HNA for
the Hidden Primary. Selection mechanisms based on HNCP [RFC7788] are
good candidates.
Secure delegation is achieved only if the DS RRset is properly set in The HNA acts as a Hidden Primary Server, which is a regular
the parent zone. Secure delegation can be performed by the HNA or authoritative DNS Server listening on the WAN interface.
the Outsourcing Infrastructures (that is the Synchronization Server
or the Public Authoritative Server(s)).
The DS RRset can be updated manually with nsupdate for example. This The DM is configured as a secondary for the Homenet Domain Name.
requires the HNA or the Outsourcing Infrastructure to be This secondary configuration has been previously agreed between the
authenticated by the DNS server hosting the parent of the Public end user and the provider of the Outsourcing Infrastructure as part
Homenet Zone. Such a trust channel between the HNA and the parent of either the provisioning or due to receipt of UPDATE messages on
DNS server may be hard to maintain with HNAs, and thus may be easier the DM Control Channel.
to establish with the Outsourcing Infrastructure. In fact, the
Public Authoritative Server(s) may use Automating DNSSEC Delegation
Trust Maintenance [RFC7344].
7. Handling Different Views The Homenet Reverse Zone MAY also be updated either with DNS UPDATE
[RFC2136] or using a primary / secondary synchronization.
The Homenet Zone provides information about the home network. Some 6.1. Securing the Synchronization Channel between HNA and DM
users may be tempted to have provide responses dependent on the
origin of the DNS query. More specifically, some users may be
tempted to provide a different view for DNS queries originating from
the home network and for DNS queries coming from the Internet. Each
view could then be associated with a dedicated Homenet Zone.
<!--Regarding {{fig-naming-arch}}, an example of an implementation of The Synchronization Channel used standard DNS request.
two distinct view could be the Homenet Zone that describes the
homenet view and the Public Homenet Zone that contains the Internet
view, with these two zones being different.-->
Note that this document does not specify how DNS queries originating First the primary notifies the secondary that the zone must be
from the home network are addressed to the Homenet Zone. This could updated and eaves the secondary to proceed with the update when
be done via hosting the DNS resolver on the HNA for example. possible/ convenient.
This section is not normative. Section 7.1 details why some nodes Then, a NOTIFY message is sent by the primary, which is a small
may only be reachable from the home network and not from the global packet that is less likely to load the secondary.
Internet. Section 7.2 briefly describes the consequences of having
distinct views such as a "home network view" and an "Internet view".
Finally, Section 7.3 provides guidance on how to resolve names that
are only significant in the home network, without creating different
views.
7.1. Misleading Reasons for Local Scope DNS Zone" Finally, the AXFR [RFC1034] or IXFR [RFC1995] query performed by the
secondary is a small packet sent over TCP (section 4.2 [RFC5936]),
which mitigates reflection attacks using a forged NOTIFY.
The motivation for supporting different views is to provide different The AXFR request from the DM to the HNA SHOULD be secured. DNS over
answers dependent on the origin of the DNS query, for reasons such TLS [RFC7858] is RECOMMENDED.
as:
1: An end user may want to have services not published on the When using TLS, the HNA MAY authenticate inbound connections from the
Internet. Services like the HNA administration interface that DM using standard mechanisms, such as a public certificate with
provides the GUI to administer your HNA might not seem advisable to baked-in root certificates on the HNA, or via DANE {!RFC6698}}
publish on the Internet. Similarly, services like the mapper that
registers the devices of your home network may also not be desirable
to be published on the Internet. In both cases, these services
should only be known or used by the network administrator. To
restrict the access of such services, the home network administrator
may choose to publish these pieces of information only within the
home network, where it might be assumed that the users are more
trusted than on the Internet. Even though this assumption may not be
valid, at least this may reduce the surface of any attack.
2: Services within the home network may be reachable using non global The HNA MAY apply a simple IP filter on inbound AXFR requests to
IP addresses. IPv4 and NAT may be one reason. On the other hand ensure they only arrive from the DM Synchronization Channel. In this
IPv6 may favor link-local or site-local IP addresses. These IP case, the HNA SHOULD regularly check (via DNS resolution) that the
addresses are not significant outside the boundaries of the home address of the DM in the filter is still valid.
network. As a result, they MAY be published in the home network
view, and SHOULD NOT be published in the Public Homenet Zone.
7.2. Consequences" 7. DM Distribution Channel
Enabling different views leads to a non-coherent naming system. The DM Distribution Channel is used for communication between the DM
Depending on where resolution is performed, some services will not be and the Public Authoritative Servers. The architecture and
available. This may be especially inconvenient with devices with communication used for the DM Distribution Channels is outside the
multiple interfaces that are attached both to the Internet via a scope of this document, and there are many existing solutions
3G/4G interface and to the home network via a WLAN interface. available e.g. rsynch, DNS AXFR, REST, DB copy.
Devices may also cache the results of name resolution, and these
cached entries may no longer be valid if a mobile device moves
between a homenet connection and an internet connection e.g. a device
temporarily loses wifi signal and switches to 3G.
Regarding local-scope IP addresses, such devices may end up with poor 8. HNA Security Policies
connectivity. Suppose, for example, that DNS resolution is performed
via the WLAN interface attached to the HNA, and the response provides
local-scope IP addresses, but the communication is initiated on the
3G/4G interface. Communications with local-scope addresses will be
unreachable on the Internet, thus aborting the communication. The
same situation occurs if a device is flip / flopping between various
WLAN networks.
Regarding DNSSEC, if the HNA does not sign the Homenet Zone and This section details security policies related to the Hidden Primary
outsources the signing process, the two views are different, because / Secondary synchronization.
one is protected with DNSSEC whereas the other is not. Devices with
multiple interfaces will have difficulty securing the naming
resolution, as responses originating from the home network may not be
signed.
For devices with all its interfaces attached to a single The Hidden Primary, as described in this document SHOULD drop any
administrative domain, that is to say the home network, or the queries from the home network. This could be implemented via port
Internet. Incoherence between DNS responses may still also occur if binding and/or firewall rules. The precise mechanism deployed is out
the device is able to perform DNS resolutions both using the DNS of scope of this document. The Hidden Primary SHOULD drop any DNS
resolving server of the home network, or one of the ISP. DNS queries arriving on the WAN interface that are not issued from the
resolution performed via the HNA or the ISP resolver may be different DM. The Hidden Primary SHOULD drop any outgoing packets other than
than those performed over the Internet. DNS NOTIFY query, SOA response, IXFR response or AXFR responses. The
Hidden Primary SHOULD drop any incoming packets other than DNS NOTIFY
response, SOA query, IXFR query or AXFR query. The Hidden Primary
SHOULD drop any non protected IXFR or AXFR exchange,depending on how
the synchronization is secured.
7.3. Guidance and Recommendations 9. DNSSEC compliant Homenet Architecture
As documented in Section 7.2, it is RECOMMENDED to avoid different [RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on both
views. If network administrators choose to implement multiple views, the authoritative server and the resolver. The resolver side is out
impacts on devices' resolution SHOULD be evaluated. of scope of this document, and only the authoritative part of the
server is considered.
As a consequence, the Homenet Zone is expected to be an exact copy of This document assumes the HNA signs the Public Homenet Zone.
the Public Homenet Zone. As a result, services that are not expected
to be published on the Internet SHOULD NOT be part of the Homenet
Zone, local-scope addresses SHOULD NOT be part of the Homenet Zone,
and when possible, the HNA SHOULD sign the Homenet Zone.
The Homenet Zone is expected to host public information only. It is Secure delegation is achieved only if the DS RRset is properly set in
not the scope of the DNS service to define local home network the parent zone. Secure delegation is performed by the HNA or the
boundaries. Instead, local scope information is expected to be Outsourcing Infrastructures.
provided to the home network using local scope naming services. mDNS
[RFC6762] DNS-SD [RFC6763] are two examples of these services.
Currently mDNS is limited to a single link network. However, future
protocols are expected to leverage this constraint as pointed out in
[RFC7558].
7.4. Homenet Reverse Zone The DS RRset can be updated manually with nsupdate for example. This
requires the HNA or the Outsourcing Infrastructure to be
authenticated by the DNS server hosting the parent of the Public
Homenet Zone. Such a trust channel between the HNA and the parent
DNS server may be hard to maintain with HNAs, and thus may be easier
to establish with the Outsourcing Infrastructure. In fact, the
Public Authoritative Server(s) may use Automating DNSSEC Delegation
Trust Maintenance [RFC7344].
10. Homenet Reverse Zone
This section is focused on the Homenet Reverse Zone. This section is focused on the Homenet Reverse Zone.
Firstly, all considerations for the Homenet Zone apply to the Homenet Firstly, all considerations for the Public Homenet Zone apply to the
Reverse Zone. The main difference between the Homenet Reverse Zone Homenet Reverse Zone. The main difference between the Homenet
and the Homenet Zone is that the parent zone of the Homenet Reverse Reverse Zone and the Homenet Zone is that the parent zone of the
Zone is most likely managed by the ISP. As the ISP also provides the Homenet Reverse Zone is most likely managed by the ISP. As the ISP
IP prefix to the HNA, it may be able to authenticate the HNA using also provides the IP prefix to the HNA, it may be able to
mechanisms outside the scope of this document e.g. the physical authenticate the HNA using mechanisms outside the scope of this
attachment point to the ISP network. If the Reverse Synchronization document e.g. the physical attachment point to the ISP network. If
Server is managed by the ISP, credentials to authenticate the HNA for the Reverse DM is managed by the ISP, credentials to authenticate the
the zone synchronization may be set automatically and transparently HNA for the zone synchronization may be set automatically and
to the end user. [I-D.ietf-homenet-naming-architecture-dhc-options] transparently to the end user.
describes how automatic configuration may be performed. [I-D.ietf-homenet-naming-architecture-dhc-options] describes how
automatic configuration may be performed.
With IPv6, the domain space for IP addresses is so large that reverse With IPv6, the domain space for IP addresses is so large that reverse
zone may be confronted with scalability issues. How the reverse zone zone may be confronted with scalability issues. How the reverse zone
is generated is out of scope of this document. is generated is out of scope of this document.
[I-D.howard-dnsop-ip6rdns] provides guidance on how to address [I-D.howard-dnsop-ip6rdns] provides guidance on how to address
scalability issues. scalability issues.
8. Renumbering 11. Renumbering
This section details how renumbering is handled by the Hidden Primary This section details how renumbering is handled by the Hidden Primary
server or the Synchronization Server. Both types of renumbering are server or the DM. Both types of renumbering are discussed i.e.
discussed i.e. "make-before-break" and "break-before-make". "make-before-break" and "break-before-make".
In the make-before-break renumbering scenario, the new prefix is In the make-before-break renumbering scenario, the new prefix is
advertised, the network is configured to prepare the transition to advertised, the network is configured to prepare the transition to
the new prefix. During a period of time, the two prefixes old and the new prefix. During a period of time, the two prefixes old and
new coexist, before the old prefix is completely removed. In the new coexist, before the old prefix is completely removed. In the
break-before-make renumbering scenario, the new prefix is advertised break-before-make renumbering scenario, the new prefix is advertised
making the old prefix obsolete. making the old prefix obsolete.
Renumbering has been extensively described in [RFC4192] and analyzed Renumbering has been extensively described in [RFC4192] and analyzed
in [RFC7010] and the reader is expected to be familiar with them in [RFC7010] and the reader is expected to be familiar with them
before reading this section. before reading this section.
8.1. Hidden Primary 11.1. Hidden Primary
In a renumbering scenario, the Hidden Primary is informed it is being In a renumbering scenario, the Hidden Primary is informed it is being
renumbered. In most cases, this occurs because the whole home renumbered. In most cases, this occurs because the whole home
network is being renumbered. As a result, the Homenet Zone will also network is being renumbered. As a result, the Public Homenet Zone
be updated. Although the new and old IP addresses may be stored in will also be updated. Although the new and old IP addresses may be
the Homenet Zone, we recommend that only the newly reachable IP stored in the Public Homenet Zone, we recommend that only the newly
addresses be published. reachable IP addresses be published.
To avoid reachability disruption, IP connectivity information To avoid reachability disruption, IP connectivity information
provided by the DNS SHOULD be coherent with the IP plane. In our provided by the DNS SHOULD be coherent with the IP plane. In our
case, this means the old IP address SHOULD NOT be provided via the case, this means the old IP address SHOULD NOT be provided via the
DNS when it is not reachable anymore. Let for example TTL be the TTL DNS when it is not reachable anymore. Let for example TTL be the TTL
associated with a RRset of the Homenet Zone, it may be cached for TTL associated with a RRset of the Public Homenet Zone, it may be cached
seconds. Let T_NEW be the time the new IP address replaces the old for TTL seconds. Let T_NEW be the time the new IP address replaces
IP address in the Homenet Zone, and T_OLD_UNREACHABLE the time the the old IP address in the Homenet Zone, and T_OLD_UNREACHABLE the
old IP is not reachable anymore. time the old IP is not reachable anymore.
In the case of the make-before-break, seamless reachability is In the case of the make-before-break, seamless reachability is
provided as long as T_OLD_UNREACHABLE - T_NEW > 2 * TTL. If this is provided as long as T_OLD_UNREACHABLE - T_NEW > 2 * TTL. If this is
not satisfied, then devices associated with the old IP address in the not satisfied, then devices associated with the old IP address in the
home network may become unreachable for 2 * TTL - (T_OLD_UNREACHABLE home network may become unreachable for 2 * TTL - (T_OLD_UNREACHABLE
- T_NEW). In the case of a break-before-make, T_OLD_UNREACHABLE = - T_NEW). In the case of a break-before-make, T_OLD_UNREACHABLE =
T_NEW, and the device may become unreachable up to 2 * TTL. T_NEW, and the device may become unreachable up to 2 * TTL.
Once the Homenet Zone file has been updated on the Hidden Primary, Once the Public Homenet Zone file has been updated on the Hidden
the Hidden Primary needs to inform the Outsourcing Infrastructure Primary, the Hidden Primary needs to inform the Outsourcing
that the Homenet Zone has been updated and that the IP address to use Infrastructure that the Public Homenet Zone has been updated and that
to retrieve the updated zone has also been updated. Both the IP address to use to retrieve the updated zone has also been
notifications are performed using regular DNS exchanges. Mechanisms updated. Both notifications are performed using regular DNS
to update an IP address provided by lower layers with protocols like exchanges. Mechanisms to update an IP address provided by lower
SCTP [RFC4960], MOBIKE [RFC4555] are not considered in this document. layers with protocols like SCTP [RFC4960], MOBIKE [RFC4555] are not
considered in this document.
The Hidden Primary SHOULD inform the Synchronization Server that the The Hidden Primary SHOULD inform the DM that the Public Homenet Zone
Homenet Zone has been updated by sending a NOTIFY payload with the has been updated by sending a NOTIFY payload with the new IP address.
new IP address. In addition, this NOTIFY payload SHOULD be In addition, this NOTIFY payload SHOULD be authenticated using SIG(0)
authenticated using SIG(0) or TSIG. When the Synchronization Server or TSIG. When the DM receives the NOTIFY payload, it MUST
receives the NOTIFY payload, it MUST authenticate it. Note that the authenticate it. Note that the cryptographic key used for the
cryptographic key used for the authentication SHOULD be indexed by authentication SHOULD be indexed by the Registered Homenet Domain
the Registered Homenet Domain contained in the NOTIFY payload as well contained in the NOTIFY payload as well as the RRSIG. In other
as the RRSIG. In other words, the IP address SHOULD NOT be used as words, the IP address SHOULD NOT be used as an index. If
an index. If authentication succeeds, the Synchronization Server authentication succeeds, the DM MUST also notice the IP address has
MUST also notice the IP address has been modified and perform a been modified and perform a reachability check before updating its
reachability check before updating its primary configuration. The primary configuration. The routability check MAY performed by
routability check MAY performed by sending a SOA request to the sending a SOA request to the Hidden Primary using the source IP
Hidden Primary using the source IP address of the NOTIFY. This address of the NOTIFY. This exchange is also secured, and if an
exchange is also secured, and if an authenticated response is authenticated response is received from the Hidden Primary with the
received from the Hidden Primary with the new IP address, the new IP address, the DM SHOULD update its configuration file and
Synchronization Server SHOULD update its configuration file and retrieve the Public Homenet Zone using an AXFR or a IXFR exchange.
retrieve the Homenet Zone using an AXFR or a IXFR exchange.
Note that the primary reason for providing the IP address is that the Note that the primary reason for providing the IP address is that the
Hidden Primary is not publicly announced in the DNS. If the Hidden Hidden Primary is not publicly announced in the DNS. If the Hidden
Primary were publicly announced in the DNS, then the IP address Primary were publicly announced in the DNS, then the IP address
update could have been performed using the DNS as described in update could have been performed using the DNS as described in
Section 8.2. Section 11.2.
8.2. Synchronization Server 11.2. Distribution Master
Renumbering of the Synchronization Server results in the Renumbering of the Distribution Master results in it changing its IP
Synchronization Server changing its IP address. The Synchronization address. As the DM is a secondary, the destination of DNS NOTIFY
Server is a secondary, so its renumbering does not impact the Homenet payloads MUST be changed, and any configuration/firewalling that
Zone. In fact, exchanges to the Synchronization Server are restricts DNS AXFR/IXFR operations MUST be updated.
restricted to the Homenet Zone synchronization. In our case, the
Hidden Primary MUST be able to send NOTIFY payloads to the
Synchronization Server.
If the Synchronization Server is configured in the Hidden Primary If the DM is configured in the Hidden Primary configuration file
configuration file using a FQDN, then the update of the IP address is using a FQDN, then the update of the IP address is performed by DNS.
performed by DNS. More specifically, before sending the NOTIFY, the More specifically, before sending the NOTIFY, the Hidden Primary
Hidden Primary performs a DNS resolution to retrieve the IP address performs a DNS resolution to retrieve the IP address of the
of the secondary. secondary.
As described in Section 8.1, the Synchronization Server DNS As described in Section 11.1, the DM DNS information SHOULD be
information SHOULD be coherent with the IP plane. Let TTL be the TTL coherent with the IP plane. The TTL of the Distribution Master name
associated with the Synchronization Server FQDN, T_NEW the time the SHOULD be adjusted appropriately prior to changing the IP address.
new IP address replaces the old one and T_OLD_UNREACHABLE the time
the Synchronization Server is not reachable anymore with its old IP
address. Seamless reachability is provided as long as
T_OLD_UNREACHABLE - T_NEW > 2 * TTL. If this condition is not met,
the Synchronization Server may be unreachable during 2 * TTL -
(T_OLD_UNREACHABLE - T_NEW). In the case of a break-before-make,
T_OLD_UNREACHABLE = T_NEW, and it may become unreachable up to 2 *
TTL.
Some DNS infrastructure uses the IP address to designate the Some DNS infrastructure uses the IP address to designate the
secondary, in which case, other mechanisms must be found. The reason secondary, in which case, other mechanisms must be found. The reason
for using IP addresses instead of names is generally to reach an for using IP addresses instead of names is generally to reach an
internal interface that is not designated by a FQDN, and to avoid internal interface that is not designated by a FQDN, and to avoid
potential bootstrap problems. Such scenarios are considered as out potential bootstrap problems. Such scenarios are considered as out
of scope in the case of home networks. of scope in the case of home networks.
[]( <!- <section {#sec-dnssec-outsrc" title="DNSSEC outsourcing 12. Operational considerations for Offline/Disconnected resolution
configuration}
In this document we assume that the Outsourcing Infrastructure MAY sign the Homenet Zone. Multiple variants MAY be proposed by the Outsourcing Infrastructure. The Outsourcing Infrastructure MAY propose signing the DNS Homenet Zone with keys generated by the Outsourcing Infrastructure and which are unknown to the HNA. Alternatively the Outsourcing Infrastructure MAY propose that the end user provides the private keys. Although not considered in this document, some end users MAY still prefer to sign their zone with their own keys that they do not communicate to the Outsourcing Infrastructure. All these alternatives result from a negotiation between the end user and the Outsourcing Infrastructure. This negotiation is performed out-of-band and is out of scope of this document.
In this document, we consider that the Outsourcing Infrastructure has all the necessary cryptographic elements to perform zone signing and key management operations.
Note that Outsourcing Infrastructure described in this document implements various functions, and thus different entities may be involved.
<list hangIndent="6" style="hanging
<t hangText="- DNS Slave functionsynchronizes the Homenet Zone
between the HNA and the Outsourcing Infrastructures. The DNS Homenet Zone SHOULD NOT be published directly on the Public Authoritative Servers, and the Public Authoritative Server(s MUST NOT respond to any DNS queries for that zone. Instead, the Outsourcing Infrastructure chooses a dedicated set of servers to serve the Public Homenet Zone: the Public Authoritative Server(s.
<t hangText="- DNS Zone Signing functionsigns the DNS Zone Homenet Zone to generate an Public Homenet Zone.
<t hangText="- Public Authoritative Server hosts the naming service for the Public Homenet Zone. Any DNS query associated with the Homenet Zone SHOULD be performed using the specific servers designated as the Public Authoritative Servers
</list>
->) This section is non-normative. It provides suggestions on
operational consideration. TBD.
9. Privacy Considerations 13. Privacy Considerations
Outsourcing the DNS Authoritative service from the HNA to a third Outsourcing the DNS Authoritative service from the HNA to a third
party raises a few privacy related concerns. party raises a few privacy related concerns.
The Homenet Zone contains a full description of the services hosted The Public Homenet Zone contains a full description of the services
in the network. These services may not be expected to be publicly hosted in the network. These services may not be expected to be
shared although their names remain accessible through the Internet. publicly shared although their names remain accessible through the
Even though DNS makes information public, the DNS does not expect to Internet. Even though DNS makes information public, the DNS does not
make the complete list of services public. In fact, making expect to make the complete list of services public. In fact, making
information public still requires the key (or FQDN) of each service information public still requires the key (or FQDN) of each service
to be known by the resolver in order to retrieve information about to be known by the resolver in order to retrieve information about
the services. More specifically, making mywebsite.example.com public the services. More specifically, making mywebsite.example.com public
in the DNS, is not sufficient to make resolvers aware of the in the DNS, is not sufficient to make resolvers aware of the
existence web site. However, an attacker may walk the reverse DNS existence web site. However, an attacker may walk the reverse DNS
zone, or use other reconnaissance techniques to learn this zone, or use other reconnaissance techniques to learn this
information as described in [RFC7707]. information as described in [RFC7707].
In order to prevent the complete Homenet Zone being published on the In order to prevent the complete Public Homenet Zone being published
Internet, AXFR queries SHOULD be blocked on the Public Authoritative on the Internet, AXFR queries SHOULD be blocked on the Public
Server(s). Similarly, to avoid zone-walking NSEC3 [RFC5155] SHOULD Authoritative Server(s). Similarly, to avoid zone-walking NSEC3
be preferred over NSEC [RFC4034]. When the Homenet Zone is [RFC5155] SHOULD be preferred over NSEC [RFC4034]. When the Public
outsourced, the end user should be aware that it provides a complete Homenet Zone is outsourced, the end user should be aware that it
description of the services available on the home network. More provides a complete description of the services available on the home
specifically, names usually provides a clear indication of the network. More specifically, names usually provides a clear
service and possibly even the device type, and as the Homenet Zone indication of the service and possibly even the device type, and as
contains the IP addresses associated with the service, they also the Public Homenet Zone contains the IP addresses associated with the
limit the scope of the scan space. service, they also limit the scope of the scan space.
In addition to the Homenet Zone, the third party can also monitor the In addition to the Public Homenet Zone, the third party can also
traffic associated with the Homenet Zone. This traffic may provide monitor the traffic associated with the Public Homenet Zone. This
an indication of the services an end user accesses, plus how and when traffic may provide an indication of the services an end user
they use these services. Although, caching may obfuscate this accesses, plus how and when they use these services. Although,
information inside the home network, it is likely that outside your caching may obfuscate this information inside the home network, it is
home network this information will not be cached. likely that outside your home network this information will not be
cached.
10. Security Considerations 14. Security Considerations
The Homenet Naming Architecture described in this document solves The Homenet Naming Architecture described in this document solves
exposing the HNA's DNS service as a DoS attack vector. exposing the HNA's DNS service as a DoS attack vector.
10.1. Names are less secure than IP addresses 14.1. HNA DM channels
The HNA DM channels are specified to include their own security
mechanisms that are designed to provide the minimum attacke surface,
and to authenticate transactions where necessary.
14.2. Names are less secure than IP addresses
This document describes how an end user can make their services and This document describes how an end user can make their services and
devices from his home network reachable on the Internet by using devices from his home network reachable on the Internet by using
names rather than IP addresses. This exposes the home network to names rather than IP addresses. This exposes the home network to
attackers, since names are expected to include less entropy than IP attackers, since names are expected to include less entropy than IP
addresses. In fact, with IP addresses, the Interface Identifier is addresses. In fact, with IP addresses, the Interface Identifier is
64 bits long leading to up to 2^64 possibilities for a given 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 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 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 hand, names used either for the home network domain or for the
devices present less entropy (livebox, router, printer, nicolas, devices present less entropy (livebox, router, printer, nicolas,
jennifer, ...) and thus potentially exposes the devices to dictionary jennifer, ...) and thus potentially exposes the devices to dictionary
attacks. attacks.
10.2. Names are less volatile than IP addresses 14.3. Names are less volatile than IP addresses
IP addresses may be used to locate a device, a host or a service. 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 However, home networks are not expected to be assigned a time
invariant prefix by ISPs. As a result, observing IP addresses only invariant prefix by ISPs. As a result, observing IP addresses only
provides some ephemeral information about who is accessing the provides some ephemeral information about who is accessing the
service. On the other hand, names are not expected to be as volatile 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 as IP addresses. As a result, logging names over time may be more
valuable than logging IP addresses, especially to profile an end valuable than logging IP addresses, especially to profile an end
user's characteristics. user's characteristics.
PTR provides a way to bind an IP address to a name. In that sense, 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 responding to PTR DNS queries may affect the end user's privacy. For
that reason end users may choose not to respond to PTR DNS queries that reason end users may choose not to respond to PTR DNS queries
and MAY instead return a NXDOMAIN response. and MAY instead return a NXDOMAIN response.
10.3. DNS Reflection Attacks 14.4. DNS Reflection Attacks
An attacker performs a reflection attack when it sends traffic to one An attacker performs a reflection attack when it sends traffic to one
or more intermediary nodes (reflectors), that in turn send back or more intermediary nodes (reflectors), that in turn send back
response traffic to the victim. Motivations for using an response traffic to the victim. Motivations for using an
intermediary node might be anonymity of the attacker, as well as intermediary node might be anonymity of the attacker, as well as
amplification of the traffic. Typically, when the intermediary node amplification of the traffic. Typically, when the intermediary node
is a DNSSEC server, the attacker sends a DNSSEC query and the victim is a DNSSEC server, the attacker sends a DNSSEC query and the victim
is likely to receive a DNSSEC response. This section analyzes how is likely to receive a DNSSEC response. This section analyzes how
the different components may be involved as a reflector in a the different components may be involved as a reflector in a
reflection attack. Section 10.4 considers the Hidden Primary, reflection attack. Section 14.5 considers the Hidden Primary,
Section 10.5 the Synchronization Server, and Section 10.6 the Public Section 14.6 the Synchronization Server, and Section 14.7 the Public
Authoritative Server(s). Authoritative Server(s).
10.4. "Reflection Attack involving the Hidden Primary 14.5. Reflection Attack involving the Hidden Primary
With the specified architecture, the Hidden Primary is only expected With the specified architecture, the Hidden Primary is only expected
to receive DNS queries of type SOA, AXFR or IXFR. This section to receive DNS queries of type SOA, AXFR or IXFR. This section
analyzes how these DNS queries may be used by an attacker to perform analyzes how these DNS queries may be used by an attacker to perform
a reflection attack. a reflection attack.
DNS queries of type AXFR and IXFR use TCP and as such are less DNS queries of type AXFR and IXFR use TCP and as such are less
subject to reflection attacks. This makes SOA queries the only subject to reflection attacks. This makes SOA queries the only
remaining practical vector of attacks for reflection attacks, based remaining practical vector of attacks for reflection attacks, based
on UDP. on UDP.
skipping to change at page 24, line 44 skipping to change at page 24, line 37
in a DDoS attack. in a DDoS attack.
SOA queries are expected to follow a very specific pattern, which SOA queries are expected to follow a very specific pattern, which
makes rate limiting techniques an efficient way to limit such makes rate limiting techniques an efficient way to limit such
attacks, and associated impact on the naming service of the home attacks, and associated impact on the naming service of the home
network. network.
Motivations for such a flood might be a reflection attack, but could Motivations for such a flood might be a reflection attack, but could
also be a resource exhaustion attack performed against the Hidden also be a resource exhaustion attack performed against the Hidden
Primary. The Hidden Primary only expects to exchange traffic with Primary. The Hidden Primary only expects to exchange traffic with
the Synchronization Server, that is its associated secondary. Even the DM, that is its associated secondary. Even though secondary
though secondary servers may be renumbered as mentioned in Section 8, servers may be renumbered as mentioned in Section 11, the Hidden
the Hidden Primary is likely to perform a DNSSEC resolution and find Primary is likely to perform a DNSSEC resolution and find out the
out the associated secondary's IP addresses in use. As a result, the associated secondary's IP addresses in use. As a result, the Hidden
Hidden Primary is likely to limit the origin of its incoming traffic Primary is likely to limit the origin of its incoming traffic based
based on the origin IP address. on the origin IP address.
With filtering rules based on IP address, SOA flooding attacks are With filtering rules based on IP address, SOA flooding attacks are
limited to forged packets with the IP address of the secondary limited to forged packets with the IP address of the secondary
server. In other words, the only victims are the Hidden Primary server. In other words, the only victims are the Hidden Primary
itself or the secondary. There is a need for the Hidden Primary to itself or the secondary. There is a need for the Hidden Primary to
limit that flood to limit the impact of the reflection attack on the limit that flood to limit the impact of the reflection attack on the
secondary, and to limit the resource needed to carry on the traffic secondary, and to limit the resource needed to carry on the traffic
by the HNA hosting the Hidden Primary. On the other hand, mitigation by the HNA hosting the Hidden Primary. On the other hand, mitigation
should be performed appropriately, so as to limit the impact on the should be performed appropriately, so as to limit the impact on the
legitimate SOA sent by the secondary. legitimate SOA sent by the secondary.
The main reason for the Synchronization Server sending a SOA query is The main reason for the DM sending a SOA query is to update the SOA
to update the SOA RRset after the TTL expires, to check the serial RRset after the TTL expires, to check the serial number upon the
number upon the receipt of a NOTIFY query from the Hidden Primary, or receipt of a NOTIFY query from the Hidden Primary, or to re-send the
to re-send the SOA request when the response has not been received. SOA request when the response has not been received. When a flood of
When a flood of SOA queries is received by the Hidden Primary, the SOA queries is received by the Hidden Primary, the Hidden Primary may
Hidden Primary may assume it is involved in an attack. assume it is involved in an attack.
There are few legitimate time slots when the secondary is expected to There are few legitimate time slots when the secondary is expected to
send a SOA query. Suppose T_NOTIFY is the time a NOTIFY is sent by send a SOA query. Suppose T_NOTIFY is the time a NOTIFY is sent by
the Hidden Primary, T_SOA the last time the SOA has been queried, TTL the Hidden Primary, T_SOA the last time the SOA has been queried, TTL
the TTL associated to the SOA, and T_REFRESH the refresh time defined the TTL associated to the SOA, and T_REFRESH the refresh time defined
in the SOA RRset. The specific time SOA queries are expected can be in the SOA RRset. The specific time SOA queries are expected can be
for example T_NOTIFY, T_SOA + 2/3 TTL, T_SOA + TTL, T_SOA + for example T_NOTIFY, T_SOA + 2/3 TTL, T_SOA + TTL, T_SOA +
T_REFRESH., and. Outside a few minutes following these specific time T_REFRESH., and. Outside a few minutes following these specific time
slots, the probability that the HNA discards a legitimate SOA query slots, the probability that the HNA discards a legitimate SOA query
is very low. Within these time slots, the probability the secondary is very low. Within these time slots, the probability the secondary
may have its legitimate query rejected is higher. If a legitimate may have its legitimate query rejected is higher. If a legitimate
SOA is discarded, the secondary will re-send SOA query every "retry SOA is discarded, the secondary will re-send SOA query every "retry
time" second until "expire time" seconds occurs, where "retry time" time" second until "expire time" seconds occurs, where "retry time"
and "expire time" have been defined in the SOA. and "expire time" have been defined in the SOA.
As a result, it is RECOMMENDED to set rate limiting policies to As a result, it is RECOMMENDED to set rate limiting policies to
protect HNA resources. If a flood lasts more than the expired time protect HNA resources. If a flood lasts more than the expired time
defined by the SOA, it is RECOMMENDED to re-initiate a defined by the SOA, it is RECOMMENDED to re-initiate a
synchronization between the Hidden Primary and the secondaries. synchronization between the Hidden Primary and the secondaries.
10.5. Reflection Attacks involving the Synchronization Server 14.6. Reflection Attacks involving the DM
The Synchronization Server acts as a secondary coupled with the The DM acts as a secondary coupled with the Hidden Primary. The
Hidden Primary. The secondary expects to receive NOTIFY query, SOA secondary expects to receive NOTIFY query, SOA responses, AXFR and
responses, AXFR and IXFR responses from the Hidden Primary. IXFR responses from the Hidden Primary.
Sending a NOTIFY query to the secondary generates a NOTIFY response Sending a NOTIFY query to the secondary generates a NOTIFY response
as well as initiating an SOA query exchange from the secondary to the as well as initiating an SOA query exchange from the secondary to the
Hidden Primary. As mentioned in [RFC1996], this is a known "benign Hidden Primary. As mentioned in [RFC1996], this is a known "benign
denial of service attack". As a result, the Synchronization Server denial of service attack". As a result, the DM SHOULD enforce rate
SHOULD enforce rate limiting on sending SOA queries and NOTIFY limiting on sending SOA queries and NOTIFY responses to the Hidden
responses to the Hidden Primary. Most likely, when the secondary is Primary. Most likely, when the secondary is flooded with valid and
flooded with valid and signed NOTIFY queries, it is under a replay signed NOTIFY queries, it is under a replay attack which is discussed
attack which is discussed in Section 10.8. The key thing here is in Section 14.9. The key thing here is that the secondary is likely
that the secondary is likely to be designed to be able to process to be designed to be able to process much more traffic than the
much more traffic than the Hidden Primary hosted on a HNA. Hidden Primary hosted on a HNA.
This paragraph details how the secondary may limit the NOTIFY This paragraph details how the secondary may limit the NOTIFY
queries. Because the Hidden Primary may be renumbered, the secondary queries. Because the Hidden Primary may be renumbered, the secondary
SHOULD NOT perform permanent IP filtering based on IP addresses. In SHOULD NOT perform permanent IP filtering based on IP addresses. In
addition, a given secondary may be shared among multiple Hidden addition, a given secondary may be shared among multiple Hidden
Primaries which make filtering rules based on IP harder to set. The Primaries which make filtering rules based on IP harder to set. The
time at which a NOTIFY is sent by the Hidden Primary is not time at which a NOTIFY is sent by the Hidden Primary is not
predictable. However, a flood of NOTIFY messages may be easily predictable. However, a flood of NOTIFY messages may be easily
detected, as a NOTIFY originated from a given Homenet Zone is detected, as a NOTIFY originated from a given Homenet Zone is
expected to have a very limited number of unique source IP addresses, expected to have a very limited number of unique source IP addresses,
even when renumbering is occurring. As a result, the secondary, MAY even when renumbering is occurring. As a result, the secondary, MAY
rate limit incoming NOTIFY queries. rate limit incoming NOTIFY queries.
On the Hidden Primary side, it is recommended that the Hidden Primary On the Hidden Primary side, it is recommended that the Hidden Primary
sends a NOTIFY as long as the zone has not been updated by the sends a NOTIFY as long as the zone has not been updated by the
secondary. Multiple SOA queries may indicate the secondary is under secondary. Multiple SOA queries may indicate the secondary is under
attack. attack.
10.6. Reflection Attacks involving the Public Authoritative Servers 14.7. Reflection Attacks involving the Public Authoritative Servers
Reflection attacks involving the Public Authoritative Server(s) are Reflection attacks involving the Public Authoritative Server(s) are
similar to attacks on any Outsourcing Infrastructure. This is not similar to attacks on any Outsourcing Infrastructure. This is not
specific to the architecture described in this document, and thus are specific to the architecture described in this document, and thus are
considered as out of scope. considered as out of scope.
In fact, one motivation of the architecture described in this In fact, one motivation of the architecture described in this
document is to expose the Public Authoritative Server(s) to attacks document is to expose the Public Authoritative Server(s) to attacks
instead of the HNA, as it is believed that the Public Authoritative instead of the HNA, as it is believed that the Public Authoritative
Server(s) will be better able to defend itself. Server(s) will be better able to defend itself.
10.7. Flooding Attack 14.8. Flooding Attack
The purpose of flooding attacks is mostly resource exhaustion, where The purpose of flooding attacks is mostly resource exhaustion, where
the resource can be bandwidth, memory, or CPU for example. the resource can be bandwidth, memory, or CPU for example.
One goal of the architecture described in this document is to limit One goal of the architecture described in this document is to limit
the surface of attack on the HNA. This is done by outsourcing the the surface of attack on the HNA. This is done by outsourcing the
DNS service to the Public Authoritative Server(s). By doing so, the DNS service to the Public Authoritative Server(s). By doing so, the
HNA limits its DNS interactions between the Hidden Primary and the HNA limits its DNS interactions between the Hidden Primary and the
Synchronization Server. This limits the number of entities the HNA DM. This limits the number of entities the HNA interacts with as
interacts with as well as the scope of DNS exchanges - NOTIFY, SOA, well as the scope of DNS exchanges - NOTIFY, SOA, AXFR, IXFR.
AXFR, IXFR.
The use of an authenticated channel with SIG(0) or TSIG between the The use of an authenticated channel with SIG(0) or TSIG between the
HNA and the Synchronization Server, enables detection of illegitimate HNA and the DM, enables detection of illegitimate DNS queries, so
DNS queries, so appropriate action may be taken - like dropping the appropriate action may be taken - like dropping the queries. If
queries. If signatures are validated, then most likely, the HNA is signatures are validated, then most likely, the HNA is under a replay
under a replay attack, as detailed in Section 10.8 attack, as detailed in Section 14.9
In order to limit the resource required for authentication, it is In order to limit the resource required for authentication, it is
recommended to use TSIG that uses symmetric cryptography over SIG(0) recommended to use TSIG that uses symmetric cryptography over SIG(0)
that uses asymmetric cryptography. that uses asymmetric cryptography.
10.8. Replay Attack 14.9. Replay Attack
Replay attacks consist of an attacker either resending or delaying a Replay attacks consist of an attacker either resending or delaying a
legitimate message that has been sent by an authorized user or legitimate message that has been sent by an authorized user or
process. As the Hidden Primary and the Synchronization Server use an process. As the Hidden Primary and the DM use an authenticated
authenticated channel, replay attacks are mostly expected to use channel, replay attacks are mostly expected to use forged DNS queries
forged DNS queries in order to provide valid traffic. in order to provide valid traffic.
From the perspective of an attacker, using a correctly authenticated From the perspective of an attacker, using a correctly authenticated
DNS query may not be detected as an attack and thus may generate a DNS query may not be detected as an attack and thus may generate a
response. Generating and sending a response consumes more resources response. Generating and sending a response consumes more resources
than either dropping the query by the defender, or generating the than either dropping the query by the defender, or generating the
query by the attacker, and thus could be used for resource exhaustion query by the attacker, and thus could be used for resource exhaustion
attacks. In addition, as the authentication is performed at the DNS attacks. In addition, as the authentication is performed at the DNS
layer, the source IP address could be impersonated in order to layer, the source IP address could be impersonated in order to
perform a reflection attack. perform a reflection attack.
Section 10.3 details how to mitigate reflection attacks and Section 14.4 details how to mitigate reflection attacks and
Section 10.7 details how to mitigate resource exhaustion. Both Section 14.8 details how to mitigate resource exhaustion. Both
sections assume a context of DoS with a flood of DNS queries. This sections assume a context of DoS with a flood of DNS queries. This
section suggests a way to limit the attack surface of replay attacks. section suggests a way to limit the attack surface of replay attacks.
As SIG(0) and TSIG use inception and expiration time, the time frame As SIG(0) and TSIG use inception and expiration time, the time frame
for replay attack is limited. SIG(0) and TSIG recommends a fudge for replay attack is limited. SIG(0) and TSIG recommends a fudge
value of 5 minutes. This value has been set as a compromise between value of 5 minutes. This value has been set as a compromise between
possibly loose time synchronization between devices and the valid possibly loose time synchronization between devices and the valid
lifetime of the message. As a result, better time synchronization lifetime of the message. As a result, better time synchronization
policies could reduce the time window of the attack. policies could reduce the time window of the attack.
skipping to change at page 28, line 5 skipping to change at page 27, line 45
hosted data hosted data
Deploying DNSSEC is recommended, since in some cases the information Deploying DNSSEC is recommended, since in some cases the information
stored in the DNS is used by the ISP or an IT department to grant stored in the DNS is used by the ISP or an IT department to grant
access. For example some servers may perform PTR DNS queries to access. For example some servers may perform PTR DNS queries to
grant access based on host names. DNSSEC mitigates lack of trust in grant access based on host names. DNSSEC mitigates lack of trust in
DNS, and it is RECOMMENDED to deploy DNSSEC on HNAs. DNS, and it is RECOMMENDED to deploy DNSSEC on HNAs.
-->) -->)
11. IANA Considerations 15. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
12. Acknowledgment 16. Acknowledgment
The authors wish to thank Philippe Lemordant for its contributions on The authors wish to thank Philippe Lemordant for its contributions on
the early versions of the draft; Ole Troan for pointing out issues the early versions of the draft; Ole Troan for pointing out issues
with the IPv6 routed home concept and placing the scope of this with the IPv6 routed home concept and placing the scope of this
document in a wider picture; Mark Townsley for encouragement and document in a wider picture; Mark Townsley for encouragement and
injecting a healthy debate on the merits of the idea; Ulrik de Bie injecting a healthy debate on the merits of the idea; Ulrik de Bie
for providing alternative solutions; Paul Mockapetris, Christian for providing alternative solutions; Paul Mockapetris, Christian
Jacquenet, Francis Dupont and Ludovic Eschard for their remarks on Jacquenet, Francis Dupont and Ludovic Eschard for their remarks on
HNA and low power devices; Olafur Gudmundsson for clarifying DNSSEC HNA and low power devices; Olafur Gudmundsson for clarifying DNSSEC
capabilities of small devices; Simon Kelley for its feedback as capabilities of small devices; Simon Kelley for its feedback as
dnsmasq implementer; Andrew Sullivan, Mark Andrew, Ted Lemon, Mikael dnsmasq implementer; Andrew Sullivan, Mark Andrew, Ted Lemon, Mikael
Abrahamson, Michael Richardson and Ray Bellis for their feedback on Abrahamson, Michael Richardson and Ray Bellis for their feedback on
handling different views as well as clarifying the impact of handling different views as well as clarifying the impact of
outsourcing the zone signing operation outside the HNA; Mark Andrew outsourcing the zone signing operation outside the HNA; Mark Andrew
and Peter Koch for clarifying the renumbering. and Peter Koch for clarifying the renumbering.
13. References 17. Annex
13.1. Normative References 17.1. Envisioned deployment scenarios
A number of deployment have been envisionned, this section aims at
providing a brief description. The use cases are not limitatives and
this section is not normative.
17.1.1. CPE Vendor
A specific vendor with specific relations with a registrar or a
registry may sell a CPE that is provisioned with provisioned domain
name. Such domain name does not need to be necessary human readable.
One possible way is that the vendor also provisions the HNA with a
private and public keys as well as a certificate. Note that these
keys are not expected to be used for DNSSEC signing. Instead these
keys are solely used by the HNA to proceed to the authentication.
Normally the keys should be necessary and sufficient to proceed to
the authentication. The reason to combine the domain name and the
key is that outsourcing infrastructure are likely handle names better
than keys and that domain names might be used as a login which
enables the key to be regenerated.
When the home network owner plugs the CPE at home, the relation
between HNA and DM is expected to work out-of-the-box.
17.1.2. Agnostic CPE
An CPE that is not preconfigured may also take advanatge to the
protocol defined in this document but some configuration steps will
be needed.
1. The owner of the home network buys a domain name to a registrar,
and as such creates an account on that registrar
2. Either the registrar is also providing the outsourcing
infrastructure or the home network needs to create a specific
account on the outsourcing infrastructure. * If the outsourcing
provider is the registrar, the outsourcing has by design a proof
of ownership of the domain name by the homenet owner. In this
case, it is expected the infrastructure provides the necessary
parameters to the home network owner to configure the HNA. A
good way to provide the parameters would be the home network be
able to copy/paste a JSON object. What matters at that point is
the outsourcing infrastructure being able to generate
authentication credentials for the HNA to authenticate itself to
the outsourcing infrastructure. This obviously requires the home
network to provide the public key gnerated by the HNA in a CSR.
o If the outsourcing infrastructure is not the registrar, then the
proof of ownership needs to be established using protocols like
ACME for example that will end in the generation of a certificate.
ACME is used here to the purpose of automating the generation of
the certificate, the CA may be a specific CA or the outsourcing
infrastructure. With that being done, the outsourcing
infrastructure has a roof of ownership and can proceed as above.
17.2. Example: Homenet Zone
This section is not normative and intends to illustrate how the HNA
builds the Homenet Zone.
As depicted in Figure 1, the Public Homenet Zone is hosted on the
Public Authoritative Server(s), whereas the Homenet Zone is hosted on
the HNA. This section considers that the HNA builds the zone that
will be effectively published on the Public Authoritative Server(s).
In other words "Homenet to Public Zone transformation" is the
identity also commonly designated as "no operation" (NOP).
In that case, the Homenet Zone should configure its Name Server RRset
(NS) and Start of Authority (SOA) with the values associated with the
Public Authoritative Server(s). This is illustrated in Figure 2.
public.primary.example.net is the FQDN of the Public Authoritative
Server(s), and IP1, IP2, IP3, IP4 are the associated IP addresses.
Then the HNA should add the additional new nodes that enter the home
network, remove those that should be removed, and sign the Homenet
Zone.
$ORIGIN example.com
$TTL 1h
@ IN SOA public.primary.example.net
hostmaster.example.com. (
2013120710 ; serial number of this zone file
1d ; secondary refresh
2h ; secondary retry time in case of a problem
4w ; secondary expiration time
1h ; maximum caching time in case of failed
; lookups
)
@ NS public.authoritative.servers.example.net
public.primary.example.net A @IP1
public.primary.example.net A @IP2
public.primary.example.net AAAA @IP3
public.primary.example.net AAAA @IP4
Figure 2: Homenet Zone
The SOA RRset is defined in [RFC1033], [RFC1035] and [RFC2308]. This
SOA is specific, as it is used for the synchronization between the
Hidden Primary and the DM and published on the DNS Public
Authoritative Server(s)..
o MNAME: indicates the primary. In our case the zone is published
on the Public Authoritative Server(s), and its name MUST be
included. If multiple Public Authoritative Server(s) are
involved, one of them MUST be chosen. More specifically, the HNA
MUST NOT include the name of the Hidden Primary.
o RNAME: indicates the email address to reach the administrator.
[RFC2142] recommends using hostmaster@domain and replacing the '@'
sign by '.'.
o REFRESH and RETRY: indicate respectively in seconds how often
secondaries need to check the primary, and the time between two
refresh when a refresh has failed. Default values indicated by
[RFC1033] are 3600 (1 hour) for refresh and 600 (10 minutes) for
retry. This value might be too long for highly dynamic content.
However, the Public Authoritative Server(s) and the HNA are
expected to implement NOTIFY [RFC1996]. So whilst shorter refresh
timers might increase the bandwidth usage for secondaries hosting
large number of zones, it will have little practical impact on the
elapsed time required to achieve synchronization between the
Outsourcing Infrastructure and the Hidden Master. As a result,
the default values are acceptable.
o EXPIRE: is the upper limit data SHOULD be kept in absence of
refresh. The default value indicated by [RFC1033] is 3600000
(approx. 42 days). In home network architectures, the HNA
provides both the DNS synchronization and the access to the home
network. This device may be plugged and unplugged by the end user
without notification, thus we recommend a long expiry timer.
o MINIMUM: indicates the minimum TTL. The default value indicated
by [RFC1033] is 86400 (1 day). For home network, this value MAY
be reduced, and 3600 (1 hour) seems more appropriate.
<<!-- ## Considerations on multiple Registered Homenet Domain Names
## are left for future versions When multiple Registered Homenet
Domains are used -like example.com, example.net, example.org, a DNS
Homenet Zone file per Registered Homenet Domain SHOULD be generated.
In order to synchronize the zone contents, the HNA may provide all
bindings in each zone files. As a result, any update MUST be
performed on all zone files, i.e. for all Registered Homenet Domains.
To limit thees updates when multiple Registered Homenet Domains are
involved, the HNA MAY fill all bindings in a specific zone file and
redirect all other zones to that zone. This can be achieved with
redirecting mechanisms like CNAME {{RFC2181}}, {{RFC1034}}, DNAME
{{RFC6672}} or CNAME+DNAME {{I-D.sury-dnsext-cname-dname}}. This is
an implementation issue to determine whether redirection mechanisms
MAY be preferred for large Homenet Zones, or when the number of
Registered Homenet Domain becomes quite large. -->>
17.3. Example: HNA necessary parameters for outsourcing
This section specifies the various parameters required by the HNA to
configure the naming architecture of this document. This section is
informational, and is intended to clarify the information handled by
the HNA and the various settings to be done.
DM may be configured with the following parameters. These 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:
o DM: The associated FQDNs or IP addresses of the DM. IP addresses
are optional and the FQDN is sufficient. To secure the binding
name and IP addresses, a DNSSEC exchange is required. Otherwise,
the IP addresses should be entered manually.
o Authentication Method: How the HNA authenticates itself to the DM.
This MAY depend on the implementation but this should cover at
least IPsec, DTLS and TSIG
o Authentication data: Associated Data. PSK only requires a single
argument. If other authentication mechanisms based on
certificates are used, then HNA private keys, certificates and
certification authority should be specified.
o Public Authoritative Server(s): The FQDN or IP addresses of the
Public Authoritative Server(s). It MAY correspond to the data
that will be set in the NS RRsets and SOA of the Homenet Zone. IP
addresses are optional and the FQDN is sufficient. To secure the
binding between name and IP addresses, a DNSSEC exchange is
required. Otherwise, the IP addresses should be entered manually.
o Registered Homenet Domain: The domain name used to establish the
secure channel. This name is used by the DM and the HNA for the
primary / secondary configuration as well as to index the NOTIFY
queries of the HNA when the HNA has been renumbered.
Setting the Homenet Zone requires the following information.
o Registered Homenet Domain: The Domain Name of the zone. Multiple
Registered Homenet Domains may be provided. This will generate
the creation of multiple Public Homenet Zones.
o Public Authoritative Server(s): The Public Authoritative Server(s)
associated with the Registered Homenet Domain. Multiple Public
Authoritative Server(s) may be provided.
Two possible methods of providing the required information would be:
JSON for forward zones [should be standardized in a similar way to
zone file layout in RFC1035]
DHCP for reverse zones [needs a separate draft]
18. References
18.1. Normative References
[RFC1033] Lottor, M., "Domain Administrators Operations Guide", [RFC1033] Lottor, M., "Domain Administrators Operations Guide",
RFC 1033, DOI 10.17487/RFC1033, November 1987, RFC 1033, DOI 10.17487/RFC1033, November 1987,
<https://www.rfc-editor.org/info/rfc1033>. <https://www.rfc-editor.org/info/rfc1033>.
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", [RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>. <https://www.rfc-editor.org/info/rfc1034>.
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
skipping to change at page 29, line 32 skipping to change at page 34, line 5
[RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS [RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS
NCACHE)", RFC 2308, DOI 10.17487/RFC2308, March 1998, NCACHE)", RFC 2308, DOI 10.17487/RFC2308, March 1998,
<https://www.rfc-editor.org/info/rfc2308>. <https://www.rfc-editor.org/info/rfc2308>.
[RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.
Wellington, "Secret Key Transaction Authentication for DNS Wellington, "Secret Key Transaction Authentication for DNS
(TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000,
<https://www.rfc-editor.org/info/rfc2845>. <https://www.rfc-editor.org/info/rfc2845>.
[RFC2930] Eastlake 3rd, D., "Secret Key Establishment for DNS (TKEY
RR)", RFC 2930, DOI 10.17487/RFC2930, September 2000,
<https://www.rfc-editor.org/info/rfc2930>.
[RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures
( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September
2000, <https://www.rfc-editor.org/info/rfc2931>. 2000, <https://www.rfc-editor.org/info/rfc2931>.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions", Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005, RFC 4034, DOI 10.17487/RFC4034, March 2005,
<https://www.rfc-editor.org/info/rfc4034>. <https://www.rfc-editor.org/info/rfc4034>.
[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for [RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
skipping to change at page 31, line 34 skipping to change at page 36, line 5
<https://www.rfc-editor.org/info/rfc7558>. <https://www.rfc-editor.org/info/rfc7558>.
[RFC7707] Gont, F. and T. Chown, "Network Reconnaissance in IPv6 [RFC7707] Gont, F. and T. Chown, "Network Reconnaissance in IPv6
Networks", RFC 7707, DOI 10.17487/RFC7707, March 2016, Networks", RFC 7707, DOI 10.17487/RFC7707, March 2016,
<https://www.rfc-editor.org/info/rfc7707>. <https://www.rfc-editor.org/info/rfc7707>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking [RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <https://www.rfc-editor.org/info/rfc7788>. 2016, <https://www.rfc-editor.org/info/rfc7788>.
13.2. Informative References [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>.
[RFC8375] Pfister, P. and T. Lemon, "Special-Use Domain
'home.arpa.'", RFC 8375, DOI 10.17487/RFC8375, May 2018,
<https://www.rfc-editor.org/info/rfc8375>.
18.2. Informative References
[I-D.howard-dnsop-ip6rdns] [I-D.howard-dnsop-ip6rdns]
Howard, L., "Reverse DNS in IPv6 for Internet Service Howard, L., "Reverse DNS in IPv6 for Internet Service
Providers", draft-howard-dnsop-ip6rdns-00 (work in Providers", draft-howard-dnsop-ip6rdns-00 (work in
progress), June 2014. progress), June 2014.
[I-D.ietf-homenet-naming-architecture-dhc-options] [I-D.ietf-homenet-naming-architecture-dhc-options]
Migault, D., Mrugalski, T., Griffiths, C., Weber, R., and Migault, D., Mrugalski, T., Griffiths, C., Weber, R., and
W. Cloetens, "DHCPv6 Options for Homenet Naming W. Cloetens, "DHCPv6 Options for Homenet Naming
Architecture", draft-ietf-homenet-naming-architecture-dhc- Architecture", draft-ietf-homenet-naming-architecture-dhc-
options-06 (work in progress), June 2018. options-06 (work in progress), June 2018.
[I-D.ietf-homenet-simple-naming]
Lemon, T., Migault, D., and S. Cheshire, "Homenet Naming
and Service Discovery Architecture", draft-ietf-homenet-
simple-naming-03 (work in progress), October 2018.
[I-D.sury-dnsext-cname-dname] [I-D.sury-dnsext-cname-dname]
Sury, O., "CNAME+DNAME Name Redirection", draft-sury- Sury, O., "CNAME+DNAME Name Redirection", draft-sury-
dnsext-cname-dname-00 (work in progress), April 2010. dnsext-cname-dname-00 (work in progress), April 2010.
Authors' Addresses Authors' Addresses
Daniel Migault Daniel Migault
Ericsson Ericsson
8275 Trans Canada Route 8275 Trans Canada Route
Saint Laurent, QC 4S 0B6 Saint Laurent, QC 4S 0B6
skipping to change at page 32, line 14 skipping to change at page 37, line 4
Authors' Addresses Authors' Addresses
Daniel Migault Daniel Migault
Ericsson Ericsson
8275 Trans Canada Route 8275 Trans Canada Route
Saint Laurent, QC 4S 0B6 Saint Laurent, QC 4S 0B6
Canada Canada
EMail: daniel.migault@ericsson.com EMail: daniel.migault@ericsson.com
Ralf Weber Ralf Weber
Nominum Nominum
2000 Seaport Blvd 2000 Seaport Blvd
Redwood City 94063 Redwood City 94063
US US
EMail: ralf.weber@nominum.com 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 Ray Hunter
Globis Consulting BV Globis Consulting BV
Weegschaalstraat 3 Weegschaalstraat 3
Eindhoven 5632CW Eindhoven 5632CW
NL NL
EMail: v6ops@globis.net EMail: v6ops@globis.net
Chris Griffiths Chris Griffiths
EMail: cgriffiths@gmail.com EMail: cgriffiths@gmail.com
Wouter Cloetens Wouter Cloetens
SoftAtHome< SoftAtHome
vaartdijk 3 701 vaartdijk 3 701
Wijgmaal 3018 Wijgmaal 3018
BE BE
EMail: cgriffiths@gmail.com EMail: wouter.cloetens@softathome.com
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