draft-ietf-homenet-front-end-naming-delegation-02.txt   draft-ietf-homenet-front-end-naming-delegation-03.txt 
HOMENET D. Migault (Ed) HOMENET D. Migault (Ed)
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Standards Track W. Cloetens Intended status: Standards Track R. Weber
Expires: November 5, 2015 SoftAtHome Expires: January 3, 2016 Nominum
R. Hunter
Globis Consulting BV
C. Griffiths C. Griffiths
Dyn
R. Weber W. Cloetens
Nominum SoftAtHome
May 4, 2015 July 2, 2015
Outsourcing Home Network Authoritative Naming Service Outsourcing Home Network Authoritative Naming Service
draft-ietf-homenet-front-end-naming-delegation-02.txt draft-ietf-homenet-front-end-naming-delegation-03.txt
Abstract Abstract
CPEs are designed to provide IP connectivity to home networks. Most RFC7368 'IPv6 Home Networking Architecture Principles' section 3.7
CPEs assign IP addresses to the nodes of the home network which makes describes architecture principles related to naming and service
it a good candidate for hosting the naming service. With IPv6, the discovery in residential home networks.
naming service makes nodes reachable from the home network as well as
from the Internet. Customer Edge Routers and other Customer Premises Equipment (CPEs)
are designed to provide IP connectivity to home networks. Most CPEs
assign IP addresses to the nodes of the home network which makes them
good candidates for hosting the naming service. IPv6 provides global
connectivity, and nodes from the home network will be reachable from
the global Internet. As a result, the naming service is expected to
be exposed on the Internet.
However, CPEs have not been designed to host such a naming service However, CPEs have not been designed to host such a naming service
exposed on the Internet. This may expose the CPEs to resource exposed on the Internet. Running a naming service visible on the
exhaustion which would make the home network unreachable, and most Internet may expose the CPEs to resource exhaustion and other
probably would also affect the home network inner communications. attacks, which could make the home network unreachable, and most
probably would also affect the internal communications of the home
network.
In addition, DNSSEC management and configuration may not be well In addition, regular end users may not understand, or possess the
understood or mastered by regular end users. Misconfiguration may necessary skills to be able to perform, DNSSEC management and
also result in naming service disruption, thus these end users may configuration. Misconfiguration may also result in naming service
prefer to rely on third party naming providers. disruption, thus these end users may prefer to rely on third party
name service providers.
This document describes a homenet naming architecture where the CPEs This document describes a homenet naming architecture, where the CPEs
manage the DNS zone associated to its home network, and outsources manage the DNS zones associated with its own home network, and
the naming service and eventually the DNSSEC management on the outsource elements of the naming service (possibly including DNSSEC
Internet to a third party designated as the Public Authoritative management) to a third party running on the Internet.
Servers.
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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 November 5, 2015. This Internet-Draft will expire on January 3, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Architecture Description . . . . . . . . . . . . . . . . . . 5 4. Architecture Description . . . . . . . . . . . . . . . . . . 6
4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 6 4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 6
4.2. Example: DNS(SEC) Homenet Zone . . . . . . . . . . . . . 8 4.2. Example: Homenet Zone . . . . . . . . . . . . . . . . . . 8
4.3. Example: CPE necessary parameters for outsourcing . . . . 10 4.3. Example: CPE necessary parameters for outsourcing . . . . 10
5. Synchronization between CPE and Public Authoritative Name 5. Synchronization between CPE and the Synchronization Server . 11
Server Sets . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1. Synchronization with a Hidden Primary . . . . . . . . . . 11 5.1. Synchronization with a Hidden Primary . . . . . . . . . . 11
5.2. Securing Synchronization . . . . . . . . . . . . . . . . 12 5.2. Securing Synchronization . . . . . . . . . . . . . . . . 12
5.3. CPE Security Policies . . . . . . . . . . . . . . . . . . 14 5.3. CPE Security Policies . . . . . . . . . . . . . . . . . . 13
6. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 14 6. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 14
6.1. Zone Signing . . . . . . . . . . . . . . . . . . . . . . 14 6.1. Zone Signing . . . . . . . . . . . . . . . . . . . . . . 14
6.2. Secure Delegation . . . . . . . . . . . . . . . . . . . . 16 6.2. Secure Delegation . . . . . . . . . . . . . . . . . . . . 16
7. Handling Different Views . . . . . . . . . . . . . . . . . . 16 7. Handling Different Views . . . . . . . . . . . . . . . . . . 16
7.1. Misleading Reasons for Local Scope DNS Zone . . . . . . . 17 7.1. Misleading Reasons for Local Scope DNS Zone . . . . . . . 17
7.2. Consequences . . . . . . . . . . . . . . . . . . . . . . 17 7.2. Consequences . . . . . . . . . . . . . . . . . . . . . . 17
7.3. Guidance and Recommendations . . . . . . . . . . . . . . 18 7.3. Guidance and Recommendations . . . . . . . . . . . . . . 18
8. Reverse Zone . . . . . . . . . . . . . . . . . . . . . . . . 18 8. Homenet Reverse Zone . . . . . . . . . . . . . . . . . . . . 19
9. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 19 9. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.1. Hidden Primary . . . . . . . . . . . . . . . . . . . . . 19 9.1. Hidden Primary . . . . . . . . . . . . . . . . . . . . . 19
9.2. Public Authoritative Name Server Set . . . . . . . . . . 21 9.2. Synchronization Server . . . . . . . . . . . . . . . . . 21
10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 21 10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 21
11. Security Considerations . . . . . . . . . . . . . . . . . . . 22 11. Security Considerations . . . . . . . . . . . . . . . . . . . 22
11.1. Names are less secure than IP addresses . . . . . . . . 22 11.1. Names are less secure than IP addresses . . . . . . . . 22
11.2. Names are less volatile than IP addresses . . . . . . . 23 11.2. Names are less volatile than IP addresses . . . . . . . 23
11.3. DNS Reflection Attacks . . . . . . . . . . . . . . . . . 23 11.3. DNS Reflection Attacks . . . . . . . . . . . . . . . . . 23
11.3.1. Reflection Attack involving the Hidden Primary . . . 23 11.3.1. Reflection Attack involving the Hidden Primary . . . 23
11.3.2. Reflection Attacks involving the Public 11.3.2. Reflection Attacks involving the Synchronization
Authoritative Name Server Set . . . . . . . . . . . 25 Server . . . . . . . . . . . . . . . . . . . . . . . 25
11.3.3. Reflection Attacks involving the Public 11.3.3. Reflection Attacks involving the Public
Authoritative Primary . . . . . . . . . . . . . . . 25 Authoritative Servers . . . . . . . . . . . . . . . 25
11.4. Flooding Attack . . . . . . . . . . . . . . . . . . . . 26 11.4. Flooding Attack . . . . . . . . . . . . . . . . . . . . 26
11.5. Replay Attack . . . . . . . . . . . . . . . . . . . . . 26 11.5. Replay Attack . . . . . . . . . . . . . . . . . . . . . 26
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
13. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 27 13. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 27
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 27 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
14.1. Normative References . . . . . . . . . . . . . . . . . . 27 14.1. Normative References . . . . . . . . . . . . . . . . . . 27
14.2. Informational References . . . . . . . . . . . . . . . . 29 14.2. Informational References . . . . . . . . . . . . . . . . 29
Appendix A. Document Change Log . . . . . . . . . . . . . . . . 30 Appendix A. Document Change Log . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
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. To access services IPv6 provides global end to end IP reachability. End users prefer to
hosted in the home network with IPv6 addresses, end users prefer to use names instead of long and complex IPv6 addresses when accessing
use names instead of long and complex IPv6 addresses. services hosted in the home network.
CPEs are already providing IPv6 connectivity to the home network and Customer Edge Routers and other Customer Premises Equipment (CPEs)
are already providing IPv6 connectivity to the home network, and
generally provide IPv6 addresses or prefixes to the nodes of the home generally provide IPv6 addresses or prefixes to the nodes of the home
network. This makes the CPEs a good candidate to manage binding network. This makes CPEs good candidates to manage the binding
between names and IP addresses of the nodes. In addition, [RFC7368] between names and IP addresses of nodes. In addition, [RFC7368]
recommends that home networks be resilient to connectivity disruption recommends that home networks be resilient to connectivity disruption
from the ISP. This requires that a dedicate device inside the home from the ISP. This could be achieved by a dedicated device inside
network manage bindings between names and IP addresses of the nodes the home network that builds the Homenet Zone, thus providing
and builds the DNS Homenet Zone. All this makes the CPE the natural bindings between names and IP addresses. All this makes the CPE the
candidate for setting the DNS(SEC) zone file of the home network. natural candidate for populating the Homenet zone.
CPEs are usually low powered devices designed for the home network, CPEs are usually low powered devices designed for the home network,
but not for heavy traffic. As a result, hosting an authoritative DNS but not for terminating heavy traffic. As a result, hosting an
service on the Internet may expose the home network to resource authoritative DNS service on the Internet may expose the home network
exhaustion, which may isolate the home network from the Internet and to resource exhaustion and other attacks. This may isolate the home
affect the services hosted by the CPEs, thus affecting the overall network from the Internet and also impact the services hosted by the
home network communications. CPEs, thus affecting overall home network communication.
In order to avoid resource exhaustion, this document describes an In order to avoid resource exhaustion and other attacks, this
architecture that outsources the authoritative naming service of the document describes an architecture that outsources the authoritative
home network. More specifically, the DNS(SEC) Homenet Zone built by naming service of the home network. More specifically, the Homenet
the CPE is outsourced to Public Authoritative Servers. These servers Zone built by the CPE is outsourced to an Outsourcing Infrastructure.
publish the corresponding DN(SEC) Public Zone on the Internet. The Outsourcing Infrastructure publishes the corresponding Public
Section 4.1 describes the architecture. In order to keep the Homenet Zone on the Internet. Section 4.1 describes the
DNS(SEC) Public Zone up-to-date Section 5 describes how the DNS(SEC) architecture. In order to keep the Public Homenet Zone up-to-date
Homenet Zone and the DN(SEC) Public Zone can be synchronized. The Section 5 describes how the Homenet Zone and the Public Homenet Zone
proposed architecture aims at deploying DNSSEC and the DNS(SEC) can be synchronized. The proposed architecture aims at deploying
Public Zone is expected to be signed with a secure delegation. The DNSSEC, and the Public Homenet Zone is expected to be signed with a
zone signing and secure delegation can be performed either by the CPE secure delegation. The zone signing and secure delegation may be
or by the Public Authoritative Servers. Section 6 discusses these performed either by the CPE or by the Outsourcing Infrastructure.
two alternatives. Section 7 discusses multiple views aspects and Section 6 discusses these two alternatives. Section 7 discusses the
provide guidance to avoid them. Section 8 discusses the case of the consequences of publishing multiple representations of the same zone
reverse zone. Section 9 discusses how renumbering should be handled. also commonly designated as views. This section provides guidance to
Finally, Section 10 and Section 11 respectively discuss privacy and limit the risks associated with multiple views. Section 8 discusses
security considerations when outsourcing the DNS Homenet Zone. management of the reverse zone. Section 9 discusses how renumbering
should be handled. Finally, Section 10 and Section 11 respectively
discuss privacy and security considerations when outsourcing the
Homenet Zone.
3. Terminology 3. Terminology
- Customer Premises Equipment: (CPE) is the router providing - Customer Premises Equipment: (CPE) is the router providing
connectivity to the home network. It is configured and managed connectivity to the home network. It might be configured and
by the end user. In this document, the CPE MAY also host managed by the end user. In this document, the CPE might also
services such as DHCPv6. This device MAY be provided by the host services such as DHCPv6. This device might be provided by
ISP. the ISP.
- Registered Homenet Domain: is the Domain Name associated to the - Registered Homenet Domain: is the Domain Name associated to the
home network. home network.
- DNS Homenet Zone: is the DNS zone associated to the home network. - Homenet Zone: is the DNS zone associated with the home network.
This zone is set by the CPE and essentially contains the It is designated by its Registered Homenet Domain. This zone
bindings between names and IP addresses of the nodes of the is built by the CPE and contains the bindings between names and
home network. In this document, the CPE does neither perform IP addresses of the nodes in the home network. The CPE
any DNSSEC management operations such as zone signing nor synchronizes the Homenet Zone with the Synchronization Server
provide an authoritative service for the zone. Both are via a hidden primary / secondary architecture. The Outsourcing
delegated to the Public Authoritative Server. The CPE Infrastructure may process the Homenet Zone - for example
synchronizes the DNS Homenet Zone with the Public Authoritative providing DNSSEC signing - to generate the Public Homenet Zone.
Server via a hidden primary / secondary architecture. The This Public Homenet Zone is then transmitted to the Public
Public Authoritative Server MAY use specific servers for the Authoritative Server(s) that publish it on the Internet.
synchronization of the DNS Homenet Zone: the Public
Authoritative Name Server Set as public available name servers
for the Registered Homenet Domain.
- DNS Homenet Reverse Zone: The reverse zone file associated to the - Public Homenet Zone: is the public version of the Homenet Zone.
DNS Homenet Zone. It is expected to be signed with DNSSEC. It is hosted by the
Public Authoritative Server(s), which are authoritative for
this zone. The Public Homenet Zone and the Homenet Zone might
be different. For example some names might not become
reachable from 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.
- Public Authoritative Server: performs DNSSEC management - Outsourcing Infrastructure: is the combination of the
operations as well as provides the authoritative service for Synchronization Server and the Public Authoritative Server(s).
the zone. In this document, the Public Authoritative Server
synchronizes the DNS Homenet Zone with the CPE via a hidden
primary / secondary architecture. The Public Authoritative
Server acts as a secondary and MAY use specific servers called
Public Authoritative Name Server Set. Once the Public
Authoritative Server synchronizes the DNS Homenet Zone, it
signs the zone and generates the DNSSEC Public Zone. Then the
Public Authoritative Server hosts the zone as an authoritative
server on the Public Authoritative Primary(ies).
- DNSSEC Public Zone: corresponds to the signed version of the DNS - Public Authoritative Servers: are the authoritative name servers
Homenet Zone. It is hosted by the Public Authoritative Server, hosting the Public Homenet Zone. Name resolution requests for
which is authoritative for this zone, and is reachable on the the Homenet Domain are sent to these servers. For resiliency
Public Authoritative Primary(ies). the Public Homenet Zone SHOULD be hosted on multiple servers.
- Public Authoritative Primary(ies): are the visible name server - Synchronization Server: is the server with which the CPE
hosting the DNSSEC Public Zone. End users' resolutions for the synchronizes the Homenet Zone. The Synchronization Server is
Homenet Domain are sent to this server, and this server is a configured as a secondary and the CPE acts as primary. There
primary for the zone. MAY be multiple Synchronization Servers, but the text assumes a
single server. In addition, the text assumes the
Synchronization Server is a separate entity. This is not a
requirement, and when the CPE signs the zone, the
synchronization function might also be operated by the Public
Authoritative Servers.
- Public Authoritative Name Server Set: is the server the CPE - Homenet Reverse Zone: The reverse zone file associated with the
synchronizes the DNS Homenet Zone. It is configured as a Homenet Zone.
secondary and the CPE acts as primary. The CPE sends
information so the DNSSEC zone can be set and served.
- Reverse Public Authoritative Primary(ies): are the visible name - Reverse Public Authoritative Servers: are the authoritative name
server hosting the DNS Homenet Reverse Zone. End users' server(s) hosting the Public Homenet Reverse Zone. Queries for
resolutions for the Homenet Domain are sent to this server, and reverse resolution of the Homenet Domain are sent to this
this server is a primary for the zone. server. Similarly to Public Authoritative Servers, for
resiliency, the Homenet Reverse Zone SHOULD be hosted on
multiple servers.
- Reverse Public Authoritative Name Server Set: is the server the - Reverse Synchronization Server: is the server with which the CPE
CPE synchronizes the DNS Homenet Reverse Zone. It is synchronizes the Homenet Reverse Zone. It is configured as a
configured as a secondary and the CPE acts as primary. The CPE secondary and the CPE acts as primary. There MAY be multiple
sends information so the DNSSEC zone can be set and served. 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 CPE signs the zone, the
synchronization function might also be operated by the Reverse
Public Authoritative Servers.
- Hidden Primary: designates the primary server of the CPE, that
synchronizes the Homenet Zone with the Synchronization Server.
A primary / secondary architecture is used between the CPE and
the Synchronization Server. The hidden primary is not expected
to serve end user queries for the Homenet Zone as a regular
primary server would. The hidden primary is only known to its
associated Synchronization Server.
4. Architecture Description 4. Architecture Description
This section describes the architecture for outsourcing the This section describes the architecture for outsourcing the
authoritative naming service from the CPE to the Public Authoritative authoritative naming service from the CPE to the Outsourcing
Primary(ies). Section 4.1 describes the architecture, Section 4.2 Infrastructure. Section 4.1 describes the architecture, Section 4.2
and Section 4.3 illustrate this architecture and shows how the and Section 4.3 illustrates this architecture and shows how the
DNS(SEC) Homenet Zone should be built by the CPE, as well as lists Homenet Zone should be built by the CPE. It also lists the necessary
the necessary parameters the CPE needs to outsource the authoritative parameters the CPE needs to be able to outsource the authoritative
naming service. These two section are informational and non naming service. These two sections are informational and non-
normative. normative.
4.1. Architecture Overview 4.1. Architecture Overview
Figure 1 provides an overview of the architecture. Figure 1 provides an overview of the architecture.
The home network is designated by the Registered Homenet Domain Name The home network is designated by the Registered Homenet Domain Name
-- example.com in Figure 1. The CPE builds the DNS(SEC) Homenet Zone -- example.com in Figure 1. The CPE builds the Homenet Zone
associated to the home network. How the DNS(SEC) Homenet Zone is associated with the home network. How the Homenet Zone is built is
built is out of the scope of this document. The CPE may host and out of the scope of this document. The CPE may host or interact with
involve multiple services like a web GUI, DHCP [RFC6644] or mDNS multiple services to determine name-to-address mappings, such as a
[RFC6762]. These services may coexist and may be used to populate web GUI, DHCP [RFC6644] or mDNS [RFC6762]. These services may
the DNS Homenet Zone. This document assumes the DNS(SEC) Homenet coexist and may be used to populate the Homenet Zone. This document
Zone has been populated with domain names that are intended to be assumes the Homenet Zone has been populated with domain names that
publicly published and that are publicly reachable. More are intended to be publicly published and that are publicly
specifically, names associated to services or devices that are not reachable. More specifically, names associated with services or
expected to be reachable from outside the home network or names bound devices that are not expected to be reachable from outside the home
to non globally reachable IP addresses MUST NOT be part of the network or names bound to non-globally reachable IP addresses MUST
DNS(SEC) Homenet Zone. NOT be part of the Homenet Zone.
Once the DNS(SEC) Homenet Zone has been built, the CPE does not host Once the Homenet Zone has been built, the CPE does not host an
the authoritative naming service for it, but instead outsources it to authoritative naming service, but instead outsources it to the
the Public Authoritative Servers. The Public Authoritative Servers Outsourcing Infrastructure. The Outsourcing Infrastructure takes the
take the DNS(SEC) Homenet as an input and publishes the DNS(SEC) Homenet Zone as an input and publishes the Public Homenet Zone. If
Public Zone. In fact the DNS(SEC) Homenet Zone and the DNS(SEC) the CPE does not sign the Homenet Zone, the Outsourcing
Public Zone have different names as they may be different. If the Infrastructure may instead sign it on behalf of the CPE. Figure 1
CPE does not sign the DNS Homenet Zone, for example, the Public provides a more detailed description of the Outsourcing
Authoritative Servers may instead sign it on behalf of the CPE. Infrastructure, but overall, it is expected that the CPE provides the
Figure 1 provides a more detailed description of the Public Homenet Zone. Then the Public Homenet Zone is derived from the
Authoritative Servers, but overall, it is expected that the CPE Homenet Zone and published on the Internet.
provides the DNS(SEC) Homenet Zone, the DNS(SEC) Public Zone is
derived from the DNS(SEC) Homenet Zone and published on the Internet.
As a result, DNS(SEC) queries from the DNS(SEC) Resolvers on the As a result, DNS queries from the DNS resolvers on the Internet are
Internet are answered by the Public Authoritative Server and do not answered by the Outsourcing Infrastructure and do not reach the CPE.
reach the CPE. Figure 1 illustrates the case of the resolution of Figure 1 illustrates the case of the resolution of node1.example.com.
node1.example.com.
home network +-------------------+ Internet home network +-------------------+ Internet
| | | |
| CPE | | CPE |
| | +----------------------+ | | +-----------------------+
+-------+ |+-----------------+| | Public Authoritative | +-------+ |+-----------------+| | Public Authoritative |
| | || DNS(SEC) Homenet|| | Servers | | | || Homenet Zone || | Server(s) |
| node1 | || Zone || |+--------------------+| | node1 | || || |+---------------------+|
| | || || ||DNS(SEC) Public Zone|| | | || || || Public Homenet Zone ||
+-------+ || Homenet Domain ||=========|| || +-------+ || Homenet Domain ||=========|| ||
|| Name || ^ || (example.com) || || Name || ^ || (example.com) ||
node1.\ || (example.com) || | |+--------------------+| node1.\ || (example.com) || | |+---------------------+|
example.com |+-----------------+| | +----------------------+ example.com |+-----------------+| | +-----------------------+
+-------------------+ | ^ | +-------------------+ | ^ |
Synchronization | | Synchronization | |
| | | |
DNSSEC resolution for node1.example.com | v DNSSEC resolution for node1.example.com | v
+----------------------+ +-----------------------+
| | | |
| DNSSEC Resolver | | DNSSEC Resolver |
| | | |
+----------------------+ +-----------------------+
Figure 1: Homenet Naming Architecture Description Figure 1: Homenet Naming Architecture Description
The Public Authoritative Servers are described in Figure 2. The The Outsourcing Infrastructure is described in Figure 2. The
Public Authoritative Name Server Set receives the DNS(SEC) Homenet Synchronization Server receives the Homenet Zone as an input. The
Zone as an input. The received zone may be transformed to output the received zone may be transformed to output the Public Homenet Zone.
DNS(SEC) Public Zone. Various operations may be performed here, Various operations may be performed here, however this document only
however this document only considers zone signing as potential considers zone signing as a potential operation. This should occur
operation. This could occur only when the CPE outsources this only when the CPE outsources this operation to the Synchronization
operation to the Public Authoritative Name Server Set. On the other Server. On the other hand, if the CPE signs the Homenet Zone itself,
hand, if the CPE signs the DNSSEC Homenet Zone itself, the zone it the zone would be collected by the Synchronization Server and
collected by the Public Authoritative Name Server Set and directly directly transferred to the Public Authoritative Server(s). These
transferred to the Public Authoritative Primary. Implications of policies are discussed and detailed in Section 6 and Section 7.
such policy are detailed in Section 6 and Section 7.
Internet Internet
+--------------------------------------------------------+ +------------------------------------------------------+
| Public Authoritative Servers | | Outsourcing Infrastructure |
+--------------------------------------------------------+ +------------------------------------------------------+
+----------------------+ +----------------------+ +----------------------+ +----------------------+
| | | | | | | |
| Public Authoritative | | Public Authoritative | | Synchronization | | Public Authoritative |
| Name Server Set | | Primaries | | Server | | Server(s) |
| | | | | | | |
| +------------------+ | X | +------------------+ | | +------------------+ | X |+--------------------+|
| | DNS(SEC) Homenet | | ^ | | DNS(SEC) Public | | | | Homenet Zone | | ^ || Public Homenet Zone||
=========>| | Zone | | | | | Zone | | =========>| | | | || ||
^ | | | | | | | | | ^ | | | | | || ||
| | | (example.com) | | | | | (example.com) | | | | | (example.com) | | | || (example.com) ||
| | +------------------+ | | | +------------------+ | | | +------------------+ | | |+--------------------+|
| +----------------------+ | +----------------------+ | +----------------------+ | +----------------------+
| Homenet to Public Zone | Homenet to Public Zone
Synchronization transformation Synchronization transformation
from the CPE from the CPE
Figure 2: Public Authoritative Servers Description Figure 2: Outsourcing Infrastructure Description
4.2. Example: DNS(SEC) Homenet Zone 4.2. Example: Homenet Zone
This section is not normative and intends to illustrate how the CPE This section is not normative and intends to illustrate how the CPE
builds the DNS(SEC) Homenet Zone. builds the Homenet Zone.
As depicted in Figure 1 and Figure 2, the DNS(SEC) Public Zone is As depicted in Figure 1 and Figure 2, the Public Homenet Zone is
hosted on the Public Authoritative Primaries, whereas the DNS(SEC) hosted on the Public Authoritative Server(s), whereas the Homenet
Homenet Zone is hosted on the CPE. Motivations for keeping these two Zone is hosted on the CPE. Motivations for keeping these two zones
zones identical are detailed in Section 7, and this section considers identical are detailed in Section 7, and this section considers that
that the CPE builds the zone that will be effectively published on the CPE builds the zone that will be effectively published on the
the Public Authoritative Primaries. In other words "Homenet to Public Authoritative Server(s). In other words "Homenet to Public
Public Zone transformation" is the identity. Zone transformation" is the identity also commonly designated as "no
operation" (NOP).
In that case, the DNS Homenet Zone should configure its Name Server In that case, the Homenet Zone should configure its Name Server RRset
RRset (NS) and Start of Authority (SOA) with the ones associated to (NS) and Start of Authority (SOA) with the values associated with the
the Public Authoritative Primaries. This is illustrated in Figure 3. Public Authoritative Server(s). This is illustrated in Figure 3.
public.primary.example.net is the FQDN of the Public Authoritative public.primary.example.net is the FQDN of the Public Authoritative
Primaries, and IP1, IP2, IP3, IP4 are the associated IP addresses. Server(s), and IP1, IP2, IP3, IP4 are the associated IP addresses.
Then the CPE should add the different new nodes that enter the home Then the CPE should add the additional new nodes that enter the home
network, remove those that should be removed and sign the DNS Homenet network, remove those that should be removed, and sign the Homenet
Zone. Zone.
$ORIGIN example.com $ORIGIN example.com
$TTL 1h $TTL 1h
@ IN SOA public.primary.example.net @ IN SOA public.primary.example.net
hostmaster.example.com. ( hostmaster.example.com. (
2013120710 ; serial number of this zone file 2013120710 ; serial number of this zone file
1d ; secondary refresh 1d ; secondary refresh
2h ; secondary retry time in case of a problem 2h ; secondary retry time in case of a problem
4w ; secondary expiration time 4w ; secondary expiration time
1h ; maximum caching time in case of failed 1h ; maximum caching time in case of failed
; lookups ; lookups
) )
@ NS public.authoritative.servers.example.net @ NS public.authoritative.servers.example.net
public.primary.example.net A @IP1 public.primary.example.net A @IP1
public.primary.example.net A @IP2 public.primary.example.net A @IP2
public.primary.example.net AAAA @IP3 public.primary.example.net AAAA @IP3
public.primary.example.net AAAA @IP4 public.primary.example.net AAAA @IP4
Figure 3: DNS Homenet Zone Figure 3: Homenet Zone
The SOA RRset is defined in [RFC1033], [RFC1035] and [RFC2308]. This The SOA RRset is defined in [RFC1033], [RFC1035] and [RFC2308]. This
SOA is specific as it is used for the synchronization between the SOA is specific, as it is used for the synchronization between the
Hidden Primary and the Public Authoritative Name Server Set and Hidden Primary and the Synchronization Server and published on the
published on the DNS Public Authoritative Primary. DNS Public Authoritative Server(s)..
- MNAME: indicates the primary. In our case the zone is published - MNAME: indicates the primary. In our case the zone is published
on the Public Authoritative Primary, and its name MUST be on the Public Authoritative Server(s), and its name MUST be
mentioned. If multiple Public Authoritative Primaries are included. If multiple Public Authoritative Server(s) are
involved, one of them MUST be chosen. More specifically, the involved, one of them MUST be chosen. More specifically, the
CPE MUST NOT place the name of the Hidden Primary. CPE MUST NOT include the name of the Hidden Primary.
- RNAME: indicates the email address to reach the administrator. - RNAME: indicates the email address to reach the administrator.
[RFC2142] recommends to use hostmaster@domain and replacing the [RFC2142] recommends using hostmaster@domain and replacing the
'@' sign by '.'. '@' sign by '.'.
- REFRESH and RETRY: indicate respectively in seconds how often - REFRESH and RETRY: indicate respectively in seconds how often
secondaries need to check the primary and the time between two secondaries need to check the primary, and the time between two
refresh when a refresh has failed. Default value indicated by refresh when a refresh has failed. Default values indicated by
[RFC1033] are 3600 (1 hour) for refresh and 600 (10 minutes) [RFC1033] are 3600 (1 hour) for refresh and 600 (10 minutes)
for retry. This value MAY be long for highly dynamic content. for retry. This value might be too long for highly dynamic
However, Public Authoritative Primaries and the CPE are content. However, the Public Authoritative Server(s) and the
expected to implement NOTIFY [RFC1996]. Then short values MAY CPE are expected to implement NOTIFY [RFC1996]. So whilst
increase the bandwidth usage for secondaries hosting large shorter refresh timers might increase the bandwidth usage for
number of zones. As a result, default values looks fine. 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.
EXPIRE: is the upper limit data SHOULD be kept in absence of EXPIRE: is the upper limit data SHOULD be kept in absence of
refresh. Default value indicated by [RFC1033] is 3600000 about refresh. The default value indicated by [RFC1033] is 3600000
42 days. In home network architectures, the CPE provides both (approx. 42 days). In home network architectures, the CPE
the DNS synchronization and the access to the home network. provides both the DNS synchronization and the access to the
This device MAY be plugged and unplugged by the end user home network. This device may be plugged and unplugged by the
without notification, thus we recommend large period. end user without notification, thus we recommend a long expiry
timer.
MINIMUM: indicates the minimum TTL. Default value indicated by MINIMUM: indicates the minimum TTL. The default value indicated by
[RFC1033] is 86400 (1 day). For home network, this value MAY [RFC1033] is 86400 (1 day). For home network, this value MAY
be reduced, and 3600 (1 hour) seems more appropriated. be reduced, and 3600 (1 hour) seems more appropriate.
4.3. Example: CPE necessary parameters for outsourcing 4.3. Example: CPE necessary parameters for outsourcing
This section specifies the various parameters required by the CPE to This section specifies the various parameters required by the CPE to
configure the naming architecture of this document. This section is configure the naming architecture of this document. This section is
informational, and is intended to clarify the information handled by informational, and is intended to clarify the information handled by
the CPE and the various settings to be done. the CPE and the various settings to be done.
Public Authoritative Name Server Set may be defined with the Synchronization Server may be configured with the following
following parameters. These parameters are necessary to establish a parameters. These parameters are necessary to establish a secure
secure channel between the CPE and the Public Authoritative Name channel between the CPE and the Synchronization Server as well as to
Server Set: specify the DNS zone that is in the scope of the communication:
- Public Authoritative Name Server Set: The associated FQDNs or IP - Synchronization Server: The associated FQDNs or IP addresses of
addresses of the Public Authoritative Server. IP addresses are the Synchronization Server. IP addresses are optional and the
optional and the FQDN is sufficient. To secure the binding FQDN is sufficient. To secure the binding name and IP
name and IP addresses, a DNSSEC exchange is required. addresses, a DNSSEC exchange is required. Otherwise, the IP
Otherwise, the IP addresses should be entered manually. addresses should be entered manually.
- Authentication Method: How the CPE authenticates itself to the - Authentication Method: How the CPE authenticates itself to the
Public Server. This MAY depend on the implementation but we Synchronization Server. This MAY depend on the implementation
should consider at least IPsec, DTLS and TSIG but this should cover at least IPsec, DTLS and TSIG
- Authentication data: Associated Data. PSK only requires a single - Authentication data: Associated Data. PSK only requires a single
argument. If other authentication mechanisms based on argument. If other authentication mechanisms based on
certificates are used, then, files for the CPE private keys, certificates are used, then CPE private keys, certificates and
certificates and certification authority should be specified. certification authority should be specified.
- Public Authoritative Primary(ies): The FQDN or IP addresses of - Public Authoritative Server(s): The FQDN or IP addresses of the
the Public Authoritative Primary. It MAY correspond to the Public Authoritative Server(s). It MAY correspond to the data
data that will be set in the NS RRsets and SOA of the DNS that will be set in the NS RRsets and SOA of the Homenet Zone.
Homenet Zone. IP addresses are optional and the FQDN is IP addresses are optional and the FQDN is sufficient. To
sufficient. To secure the binding name and IP addresses, a secure the binding between name and IP addresses, a DNSSEC
DNSSEC exchange is required. Otherwise, the IP addresses exchange is required. Otherwise, the IP addresses should be
should be entered manually. entered manually.
- Registered Homenet Domain: The domain name the Public - Registered Homenet Domain: The domain name used to establish the
Authoritative is configured for DNS secondary, DNSSEC zone secure channel. This name is used by the Synchronization
signing and DNSSEC zone hosting. Server and the CPE for the primary / secondary configuration as
well as to index the NOTIFY queries of the CPE when the CPE has
been renumbered.
Setting the DNS(SEC) Homenet Zone requires the following information. Setting the Homenet Zone requires the following information.
- Registered Homenet Domain: The Domain Name of the zone. Multiple - Registered Homenet Domain: The Domain Name of the zone. Multiple
Registered Homenet Domain may be provided. This will generate Registered Homenet Domains may be provided. This will generate
the creation of multiple DNS Homenet Zones. the creation of multiple Public Homenet Zones.
- Public Authoritative Primaries: The public authoritative servers - Public Authoritative Server(s): The Public Authoritative
associated to the Registered Homenet Domain. Multiple public Server(s) associated with the Registered Homenet Domain.
authoritative server may be provided. Multiple Public Authoritative Server(s) may be provided.
5. Synchronization between CPE and Public Authoritative Name Server 5. Synchronization between CPE and the Synchronization Server
Sets
The DNS(SEC) Homenet Reverse Zone and the DNS Homenet Zone can be The Homenet Reverse Zone and the Homenet Zone MAY be updated either
updated either with DNS update [RFC2136] or using a primary / with DNS UPDATE [RFC2136] or using a primary / secondary
secondary synchronization. The primary / secondary mechanism is synchronization. The primary / secondary mechanism is preferred as
preferred as it better scales and avoids DoS attacks: First the it scales better and avoids DoS attacks: First the primary notifies
primary notifies the secondary the zone must be updated, and leaves the secondary that the zone must be updated and leaves the secondary
the secondary to proceed to the update when possible. Then, the to proceed with the update when possible. Then, a NOTIFY message is
NOTIFY message sent by the primary is a small packet that is less sent by the primary, which is a small packet that is less likely to
likely to load the secondary. At last, the AXFR query performed by load the secondary. Finally, the AXFR query performed by the
the secondary is a small packet sent over TCP (section 4.2 [RFC5936]) secondary is a small packet sent over TCP (section 4.2 [RFC5936]),
which makes unlikely the secondary to perform reflection attacks with which mitigates reflection attacks using a forged NOTIFY. On the
a forged NOTIFY. On the other hand, DNS updates can use UDP, packets other hand, DNS UPDATE (which can be transported over UDP), requires
require more processing then a NOTIFY, and they do not provide the more processing than a NOTIFY, and does not allow the server to
server the opportunity to post-pone the update. perform asynchronous updates.
This document recommends the use of a primary / secondary mechanism This document RECOMMENDS use of a primary / secondary mechanism
instead of the use of nsupdates. This section details the primary / instead of the use of DNS UPDATE. This section details the primary /
secondary mechanism. secondary mechanism.
5.1. Synchronization with a Hidden Primary 5.1. Synchronization with a Hidden Primary
Uploading and dynamically updating the zone file on the Public Uploading and dynamically updating the zone file on the
Authoritative Name Server Set can be seen as zone provisioning Synchronization Server can be seen as zone provisioning between the
between the CPE (Hidden Primary) and the Public Authoritative Name CPE (Hidden Primary) and the Synchronization Server (Secondary
Server Set (Secondary Server). This can be handled either in band or Server). This can be handled either in band or out of band.
out of band.
The Public Authoritative Name Server Set is configured as a secondary The Synchronization Server is configured as a secondary for the
for the Homenet Domain Name. This secondary configuration has been Homenet Domain Name. This secondary configuration has been
previously agreed between the end user and the provider of the Public previously agreed between the end user and the provider of the
Authoritative Name Server Sets. In order to set the primary/ Synchronization Server. In order to set the primary / secondary
secondary architecture, the CPE acts as a Hidden Primary Server, architecture, the CPE acts as a Hidden Primary Server, which is a
which is a regular Authoritative DNS(SEC) Server listening on the WAN regular authoritative DNS Server listening on the WAN interface.
interface.
The Hidden Primary Server is expected to accept SOA [RFC1033], AXFR The Hidden Primary Server SHOULD accept SOA [RFC1033], AXFR
[RFC1034], and IXFR [RFC1995] queries from its configured secondary [RFC1034], and IXFR [RFC1995] queries from its configured secondary
DNS servers. The Hidden Primary Server SHOULD send NOTIFY messages DNS server(s). The Hidden Primary Server SHOULD send NOTIFY messages
[RFC1996] in order to update Public DNS server zones as updates [RFC1996] in order to update Public DNS server zones as updates
occur. Because, DNS Homenet Zones are likely to be small, CPE MUST occur. Because, the Homenet Zones are likely to be small, the CPE
implement AXFR and SHOULD implement IXFR. MUST implement AXFR and SHOULD implement IXFR.
Hidden Primary Server differs from a regular authoritative server for Hidden Primary Server differs from a regular authoritative server for
the home network by: the home network by:
- Interface Binding: the Hidden Primary Server listens on the WAN - Interface Binding: the Hidden Primary Server listens on the WAN
Interface, whereas a regular authoritative server for the home Interface, whereas a regular authoritative server for the home
network would listen on the home network interface. network would listen on the home network interface.
- Limited exchanges: the purpose of the Hidden Primary Server is to - Limited exchanges: the purpose of the Hidden Primary Server is to
synchronizes with the Public Authoritative Name Server Set, not synchronize with the Synchronization Server, not to serve any
to serve zone. As a result, exchanges are performed with zones to end users. As a result, exchanges are performed with
specific nodes (the Public Authoritative Name Server Sets). specific nodes (the Synchronization Server). Further, exchange
Then exchange types are limited. The only legitimate exchanges types are limited. The only legitimate exchanges are: NOTIFY
are: NOTIFY initiated by the Hidden Primary and IXFR or AXFR initiated by the Hidden Primary and IXFR or AXFR exchanges
exchanges initiated by the Public Authoritative Name Server initiated by the Synchronization Server. On the other hand,
Set. On the other hand regular authoritative servers would regular authoritative servers would respond to any hosts, and
respond any hosts on the home network, and any DNS(SEC) query any DNS query would be processed. The CPE SHOULD filter IXFR/
would be considered. The CPE SHOULD filter IXFR/AXFR traffic AXFR traffic and drop traffic not initiated by the
and drop traffic not initiated by the Public Authoritative Name Synchronization Server. The CPE MUST listen for DNS on TCP and
Server Set. The CPE MUST listen for DNS on TCP and UDP and at UDP and MUST at least allow SOA lookups of the Homenet Zone.
least allow SOA lookups to the DNS Homenet Zone.
5.2. Securing Synchronization 5.2. Securing Synchronization
Exchange between the Public Authoritative Name Server Sets and the Exchange between the Synchronization Server and the CPE MUST be
CPE MUST be secured, at least for integrity protection and for secured, at least for integrity protection and for authentication.
authentication.
TSIG [RFC2845] or SIG(0) [RFC2931] can be used to secure the DNS TSIG [RFC2845] or SIG(0) [RFC2931] MAY be used to secure the DNS
communications between the CPE and the Public DNS(SEC) Servers. TSIG communications between the CPE and the Synchronization Server. TSIG
uses a symmetric key which can be managed by TKEY [RFC2930]. uses a symmetric key which can be managed by TKEY [RFC2930].
Management of the key involved in SIG(0) is performed through zone Management of the key involved in SIG(0) is performed through zone
updates. How to roll the keys with SIG(0) is out-of-scope of this updates. How keys are rolled over with SIG(0) is out-of-scope of
document. The advantage of these mechanisms is that they are only this document. The advantage of these mechanisms is that they are
associated with the DNS application. Not relying on shared libraries only associated with the DNS application. Not relying on shared
ease testing and integration. On the other hand, using TSIG, TKEY or libraries eases testing and integration. On the other hand, using
SIG(0) requires these mechanisms to be implemented on the DNS(SEC) TSIG, TKEY or SIG(0) requires these mechanisms to be implemented on
Server's implementation running on the CPE, which adds codes. the CPE, which adds code and complexity. Another disadvantage is
that TKEY does not provide authentication mechanisms.
Another disadvantage is that TKEY does not provide authentication
mechanism.
Protocols like TLS [RFC5246] / DTLS [RFC6347] can be used to secure Protocols like TLS [RFC5246] / DTLS [RFC6347] MAY be used to secure
the transactions between the Public Authoritative Name Server Sets the transactions between the Synchronization Server and the CPE. The
and the CPE. The advantage of TLS/DTLS is that this technology is advantage of TLS/DTLS is that this technology is widely deployed, and
widely deployed, and most of the boxes already embeds a TLS/DTLS most of the devices already embed TLS/DTLS libraries, possibly also
libraries, eventually taking advantage of hardware acceleration. taking advantage of hardware acceleration. Further, TLS/DTLS
Then TLS/DTLS provides authentication facilities and can use provides authentication facilities and can use certificates to
certificates to authenticate the Public Authoritative Name Server Set authenticate the Synchronization Server and the CPE. On the other
and the CPE. On the other hand, using TLS/DTLS requires to integrate hand, using TLS/DTLS requires implementing DNS exchanges over TLS/
DNS exchange over TLS/DTLS, as well as a new service port. This is DTLS, as well as a new service port. This document therefore does
why we do not recommend this option. NOT RECOMMEND this option.
IPsec [RFC4301] IKEv2 [RFC7296] can also be used to secure the IPsec [RFC4301] IKEv2 [RFC7296] MAY also be used to secure
transactions between the CPE and the Public Authoritative Servers. transactions between the CPE and the Synchronization Server.
Similarly to TLS/DTLS, most CPE already embeds a IPsec stack, and Similarly to TLS/DTLS, most CPEs already embed an IPsec stack, and
IKEv2 provides multiple authentications possibilities with its EAP IKEv2 supports multiple authentication mechanisms via the EAP
framework. In addition, IPsec can be used to protect the DNS framework. In addition, IPsec can be used to protect DNS exchanges
exchanges between the CPE and the Public Authoritative Servers between the CPE and the Synchronization Server without any
without any modifications of the DNS Servers or client. DNS modifications of the DNS server or client. DNS integration over
integration over IPsec only requires an additional security policy in IPsec only requires an additional security policy in the Security
the Security Policy Database. One disadvantage of IPsec is that it Policy Database (SPD). One disadvantage of IPsec is that NATs and
hardly goes through NATs and firewalls. However, in our case, the firewall traversal may be problematic. However, in our case, the CPE
CPE is connected to the Internet, and IPsec communication between the is connected to the Internet, and IPsec communication between the CPE
CPE and Public Authoritative Name Server Set SHOULD NOT be impacted and the Synchronization Server should not be impacted by middle
by middle boxes. boxes.
How the PSK can be used by any of the TSIG, TLS/DTLS or IPsec How the PSK can be used by any of the TSIG, TLS/DTLS or IPsec
protocols: Authentication based on certificates implies a mutual protocols: Authentication based on certificates implies a mutual
authentication and thus requires the CPE to manage a private key, a authentication and thus requires the CPE to manage a private key, a
public key or certificates as well as Certificate Authorities. This public key, or certificates, as well as Certificate Authorities.
adds complexity to the configuration especially on the CPE side. For This adds complexity to the configuration especially on the CPE side.
this reason, we recommend that CPE MAY use PSK or certificate base For this reason, we RECOMMEND that the CPE MAY use PSK or certificate
authentication and that Public Authoritative Servers Servers MUST base authentication, and that the Synchronization Server MUST support
support PSK and certificate based authentication. PSK and certificate based authentication.
Note also that authentication of the messages exchanged between the Note also that authentication of message exchanges between the CPE
CPE and the Public Authoritative Name Server Set should not involve and the Synchronization Server SHOULD NOT use the external IP address
the IP address to index the appropriated keys. As detailed in of the CPE to index the appropriate keys. As detailed in Section 9,
Section 9, the IP addresses of the Public Authoritative Name Server the IP addresses of the Synchronization Server and the Hidden Primary
Set and the Hidden Primary are subject to change, for example while are subject to change, for example while the network is being
the network is being renumbered. This means that the necessary keys renumbered. This means that the necessary keys to authenticate
to authenticate transaction must not be indexed using the IP and be transaction SHOULD NOT be indexed using the IP address, and SHOULD be
resilient to IP updates. resilient to IP address changes.
5.3. CPE Security Policies 5.3. CPE Security Policies
This section details security policies related to the Hidden Primary This section details security policies related to the Hidden Primary
/ Secondary synchronization. / Secondary synchronization.
The Hidden Primary, as described in this document SHOULD drop any The Hidden Primary, as described in this document SHOULD drop any
queries from the home network. This can be performed with port queries from the home network. This could be implemented via port
binding and/or firewall rules. binding and/or firewall rules. The precise mechanism deployed is out
of scope of this document.
The Hidden Primary SHOULD drop on the WAN interface any DNS queries The Hidden Primary SHOULD drop any DNS queries arriving on the WAN
that is not issued from the Public Authoritative Name Server Set. interface that are not issued from the Synchronization Server.
The Hidden Primary SHOULD drop any outgoing packets other than DNS The Hidden Primary SHOULD drop any outgoing packets other than DNS
NOTIFY query, SOA response, IXFR response or AXFR responses. NOTIFY query, SOA response, IXFR response or AXFR responses.
The Hidden Primary SHOULD drop any incoming packets other than DNS The Hidden Primary SHOULD drop any incoming packets other than DNS
NOTIFY response, SOA query, IXFR query or AXFR query. NOTIFY response, SOA query, IXFR query or AXFR query.
The Hidden Primary SHOULD drop any non protected IXFR or AXFR The Hidden Primary SHOULD drop any non protected IXFR or AXFR
exchange. This depends how the synchronization is secured. exchange,depending on how the synchronization is secured.
6. DNSSEC compliant Homenet Architecture 6. DNSSEC compliant Homenet Architecture
[RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on the [RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on both
both the authoritative server and the resolver. The resolver side is the authoritative server and the resolver. The resolver side is out
out of scope of this document, and only the authoritative part is of scope of this document, and only the authoritative part of the
considered. server is considered.
Deploying DNSSEC requires signing the zone and configuring a secure Deploying DNSSEC requires signing the zone and configuring a secure
delegation. As described in Section 4.1, signing can be performed by delegation. As described in Section 4.1, signing can be performed
the CPE or by the Public Authoritative Name Server Sets. Section 6.1 either by the CPE or by the Outsourcing Infrastructure. Section 6.1
details the implications of these two alternatives. Similarly, the details the implications of these two alternatives. Similarly, the
secure delegation can be performed by the CPE or by the Public secure delegation can be performed by the CPE or by the Outsourcing
Authoritative Servers. Section 6.2 discusses these two alternatives. Infrastructure. Section 6.2 discusses these two alternatives.
6.1. Zone Signing 6.1. Zone Signing
This section discusses the pros and cons when zone signing is This section discusses the pros and cons when zone signing is
performed by the CPE or by the Public Authoritative Name Servers Set. performed by the CPE or by the Outsourcing Infrastructure. It is
It is recommended the CPE signs the zone unless there is a strong RECOMMENDED that the CPE signs the zone unless there is a strong
argument against it, like a CPE that is not able to sign the zone. argument against this, such as a CPE that is not capable of signing
In that case zone signing may be performed by the Public the zone. In that case zone signing MAY be performed by the
Authoritative Name Servers Set on behalf of the CPE. Outsourcing Infrastructure on behalf of the CPE.
Reasons for signing the zone by the CPE are: Reasons for signing the zone by the CPE are:
- 1: Keeping the Homenet Zone and the Public Zone equals to securely - 1: Keeping the Homenet Zone and the Public Homenet Zone equal to
optimize DNS resolution. As the Public Zone is signed with securely optimize DNS resolution. As the Public Zone is signed
DNSSEC, RRsets are authenticated and thus DNS responses can be with DNSSEC, RRsets are authenticated, and thus DNS responses
validated even though they are not provided by the can be validated even though they are not provided by the
authoritative server. This provides the CPE the ability to authoritative server. This provides the CPE the ability to
respond on behalf of the Public Authoritative Primary. This respond on behalf of the Public Authoritative Server(s). This
could be useful for example if, in the future, the CPE could could be useful for example if, in the future, the CPE
announce to the home network that the CPE can act a a local announces to the home network that the CPE can act as a local
authoritative primary or equivalent for the Homenet Zone. authoritative primary or equivalent for the Homenet Zone.
Currently the CPE is not expected to receive authoritative DNS Currently the CPE is not expected to receive authoritative DNS
queries as its IP address is not mentioned in the Public Zone. queries, as its IP address is not mentioned in the Public
On the other hand most CPEs host a resolving function, and Homenet Zone. On the other hand most CPEs host a resolving
could be configured to perform a local lookup to the Homenet function, and could be configured to perform a local lookup to
Zone instead of initiating a DNS exchange with the Public the Homenet Zone instead of initiating a DNS exchange with the
Authoritative Primary. Note that outsourcing the zone signing Public Authoritative Server(s). Note that outsourcing the zone
operation requires that all DNSSEC queries be cached to perform signing operation means that all DNSSEC queries SHOULD be
a local lookup, otherwise a resolution with the Public cached to perform a local lookup, otherwise a resolution with
Authoritative Primary is performed. the Public Authoritative Server(s) would be performed.
- 2: Keeping the Homenet Zone and the Public Zone equals to securely - 2: Keeping the Homenet Zone and the Public Homenet Zone equal to
address the connectivity disruption independence exposed in securely address the connectivity disruption independence
[RFC7368] section 4.4.1 and 3.7.5. As local lookups are detailed in [RFC7368] section 4.4.1 and 3.7.5. As local
possible in case of network disruption, communications within lookups are possible in case of network disruption,
the home network can still rely on the DNSSEC service. Note communications within the home network can still rely on the
that outsourcing the zone signing operation does not address DNSSEC service. Note that outsourcing the zone signing
connectivity disruption independence with DNSSEC. Instead operation does not address connectivity disruption independence
local lookup would provide DNS as opposed to DNSSEC responses with DNSSEC. Instead local lookup would provide DNS as opposed
provided by the Public Authoritative Primaries. to DNSSEC responses provided by the Public Authoritative
Server(s).
- 3: Keeping the Homenet Zone and the Public Zone equals to - 3: Keeping the Homenet Zone and the Public Homenet Zone equal to
guarantee coherence between DNS(SEC) responses. Using a unique guarantee coherence between DNS responses. Using a unique zone
zone is one way to guarantee uniqueness of the responses among is one way to guarantee uniqueness of the responses among
servers and places. Issues generated by different views are servers and places. Issues generated by different views are
discussed in more details in Section 7. discussed in more details in Section 7.
- 2: Privacy and Integrity of the DNS Zone are better guaranteed. - 2: Privacy and Integrity of the DNSSEC Homenet Zone are better
When the Zone is signed by the CPE, it makes modification of guaranteed. When the Zone is signed by the CPE, it makes
the DNS data -- for example for flow redirection -- not modification of the DNS data -- for example for flow
possible. As a result, signing the Homenet Zone by the CPE redirection -- impossible. As a result, signing the Homenet
provides better protection for the end user privacy. Zone by the CPE provides better protection for end user
privacy.
Reasons for signing the zone by the Public Authoritative Servers are: Reasons for signing the zone by the Outsourcing Infrastructure are:
- 1: The CPE is not able to sign the zone, most likely because its - 1: The CPE may not be capable of signing the zone, most likely
firmware does not make it possible. However the reason is because its firmware does not support this function. However
expected to be less and less valid over time. this reason is expected to become less and less valid over
time.
- 2: Outsourcing DNSSEC management operations. Management - 2: Outsourcing DNSSEC management operations. Management
operations involve key-roll over which can be done operations involve key roll-over, which can be performed
automatically by the CPE and transparently for the end user. automatically by the CPE and transparently for the end user.
As result avoiding DNSSEC management is mostly motivated by bad Avoiding DNSSEC management is mostly motivated by bad software
software implementations. implementations.
- 3: Reducing the impact of CPE replacement on the Public Zone. - 3: Reducing the impact of CPE replacement on the Public Homenet
Unless the CPE private keys are backuped, CPE replacement Zone. Unless the CPE private keys can be extracted and stored
results in a emergency key roll over. This can be mitigated off-device, CPE hardware replacement will result in an
also by using relatively small TTLs. emergency key roll-over. This can be mitigated by using
relatively small TTLs.
- 4: Reducing configuration impacts on the end user. Unless there - 4: Reducing configuration impact on the end user. Unless there
are some zero configuration mechanisms to provide credentials are zero configuration mechanisms in place to provide
between the new CPE and the Public Authoritative Name Server credentials between the new CPE and the Synchronization Server,
Sets. Authentications to Public Authoritative Name Server Set authentication associations between the CPE and the
should be re-configured. As CPE replacement is not expected to Synchronization Server would need to be re-configured. As CPE
happen regularly, end users may not be at ease with such replacement is not expected to happen regularly, end users may
configuration settings. However, mechanisms as described in not be at ease with such configuration settings. However,
mechanisms as described in
[I-D.ietf-homenet-naming-architecture-dhc-options] use DHCP [I-D.ietf-homenet-naming-architecture-dhc-options] use DHCP
Options to outsource the configuration and avoid this issue. Options to outsource the configuration and avoid this issue.
- 5: Public Authoritative Servers are more likely to handle securely - 5: The Outsourcing Infrastructure is more likely to handle private
private keys than the CPE. However, having all private keys more securely than the CPE. However, having all private
information at one place may also balance that risk. keys in one place may also nullify that benefit.
6.2. Secure Delegation 6.2. Secure Delegation
The secure delegation is set if the DS RRset is properly set in the Secure delegation is achieved only if the DS RRset is properly set in
parent zone. Secure delegation can be performed by the CPE or the the parent zone. Secure delegation can be performed by the CPE or
Public Authoritative Servers. the Outsourcing Infrastructures (that is the Synchronization Server
or the Public Authoritative Server(s)).
The DS RRset can be updated manually by the CPE or the Public The DS RRset can be updated manually with nsupdate for example. This
Authoritative Servers. This can be used then with nsupdate for requires the CPE or the Outsourcing Infrastructure to be
example but requires the CPE or the Public Authoritative Server to be authenticated by the DNS server hosting the parent of the Public
authenticated by the Parent Zone Server. Such a trust channel Homenet Zone. Such a trust channel between the CPE and the parent
between the CPE and the Parent Zone server may be hard to maintain, DNS server may be hard to maintain with CPEs, and thus may be easier
and thus may be easier to establish with the Public Authoritative to establish with the Outsourcing Infrastructure. In fact, the
Server. On the other hand, [RFC7344] may mitigate such issues. Public Authoritative Server(s) may use Automating DNSSEC Delegation
Trust Maintenance [RFC7344].
7. Handling Different Views 7. Handling Different Views
The DNS Homenet Zone provides information about the home network and The Homenet Zone provides information about the home network. Some
some user may be tempted to have different information regarding the users may be tempted to have provide responses dependent on the
origin of the DNS query. More specifically, some users may be origin of the DNS query. More specifically, some users may be
tempted to provide a different view for DNS queries originating from tempted to provide a different view for DNS queries originating from
the home network and for DNS queries coming from the wild Internet. the home network and for DNS queries coming from the Internet. Each
Each view can be associated to a dedicated Homenet Zone. Note that view could then be associated with a dedicated Homenet Zone. Note
this document does not specify how DNS queries coming from the home that this document does not specify how DNS queries originating from
network are addressed to the DNS(SEC) Homenet Zone. This could be the home network are addressed to the Homenet Zone. This could be
done via the DNS resolver hosted on the CPE for example. done via hosting the DNS resolver on the CPE for example.
This section is not normative. Section 7.1 details why some nodes This section is not normative. Section 7.1 details why some nodes
may only be reachable from the home network and not from the global may only be reachable from the home network and not from the global
Internet. Section 7.2 briefly describes the consequences of having Internet. Section 7.2 briefly describes the consequences of having
distinct views such as a "home network view" and a "Internet view". distinct views such as a "home network view" and an "Internet view".
Finally, Section 7.3 provides guidance to on how to resolve names Finally, Section 7.3 provides guidance on how to resolve names that
that are only significant in the home network without creating are only significant in the home network, without creating different
different views. views.
7.1. Misleading Reasons for Local Scope DNS Zone 7.1. Misleading Reasons for Local Scope DNS Zone
The main motivation to handle different views is to provide different The motivation for supporting different views is to provide different
information depending on the location the DNS query is emitted. Here answers dependent on the origin of the DNS query, for reasons such
are a few motivations for doing so: as:
- 1: An end user may want to have services not published on the - 1: An end user may want to have services not published on the
Internet. Services like the CPE administration interface that Internet. Services like the CPE administration interface that
provides the GUI to administrate your CPE may not be published provides the GUI to administer your CPE might not seem
on the Internet. Similarly services like the mapper that advisable to publish on the Internet. Similarly, services like
registers the devices of your home network may not be published the mapper that registers the devices of your home network may
on the Internet. In both case, these services should only be also not be desirable to be published on the Internet. In both
known/used by the network administrator. To restrict the cases, these services should only be known or used by the
access of such services, the home network administrator may network administrator. To restrict the access of such
chose to publish these information only within the home services, the home network administrator may choose to publish
network, where it may suppose users are more trustable then on these pieces of information only within the home network, where
the Internet. Even though, this assumption may not be valid, it might be assumed that the users are more trusted than on the
at least, this reduces the surface of attack. 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 - 2: Services within the home network may be reachable using non
global IP addresses. IPv4 and NAT may be one reason. On the global IP addresses. IPv4 and NAT may be one reason. On the
other hand IPv6 may favor link-local or site-local IP other hand IPv6 may favor link-local or site-local IP
addresses. These IP addresses are not significant outside the addresses. These IP addresses are not significant outside the
boundaries of the home network. As a result, they may be boundaries of the home network. As a result, they MAY be
published in the home network view, and should not be published published in the home network view, and SHOULD NOT be published
in the Internet. in the Public Homenet Zone.
- 3: If the CPE does not sign the Homenet Zone and outsource the
signing process, the two views are at least different since,
one is protected with DNSSEC whereas the other is not.
7.2. Consequences 7.2. Consequences
Enabling different views leads to a non-coherent naming system. Enabling different views leads to a non-coherent naming system.
Basically, depending on where resolution is performed, some services Depending on where resolution is performed, some services will not be
will not be available. This may be especially inconvenient with available. This may be especially inconvenient with devices with
devices with multiple interfaces that are attached both to the multiple interfaces that are attached both to the Internet via a
Internet via a 3G/4G interface and to the home network via a WLAN 3G/4G interface and to the home network via a WLAN interface.
interface. 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 device may end up with poor Regarding local-scope IP addresses, such devices may end up with poor
connectivity. Suppose, for example, the DNS resolution is performed connectivity. Suppose, for example, that DNS resolution is performed
via the WLAN interface attached to the CPE, the response provides via the WLAN interface attached to the CPE, and the response provides
local-scope IP addresses and the communication is initiated on the local-scope IP addresses, but the communication is initiated on the
3G/4G interface. Communications with local-scope addresses will be 3G/4G interface. Communications with local-scope addresses will be
unreachable on the Internet, thus aborting the communication. The unreachable on the Internet, thus aborting the communication. The
same situation occurs if a device is flip / flopping between various same situation occurs if a device is flip / flopping between various
WLAN networks. WLAN networks.
Regarding DNSSEC, devices with multiple interfaces will have Regarding DNSSEC, if the CPE does not sign the Homenet Zone and
difficulties to secure the naming resolution as responses emitted outsources the signing process, the two views are different, because
from the home network may not be signed. 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 For devices with all its interfaces attached to a single
administrative domain, that is to say the home network or the administrative domain, that is to say the home network, or the
Internet. Incoherence between DNS responses may also happen if the Internet. Incoherence between DNS responses may still also occur if
device is able to perform DNS resolutions. DNS resolutions performed the device is able to perform DNS resolutions both using the DNS
via the CPE resolver may be different then those performed over the resolving server of the home network, or one of the ISP. DNS
Internet. resolution performed via the CPE or the ISP resolver may be different
than those performed over the Internet.
7.3. Guidance and Recommendations 7.3. Guidance and Recommendations
As exposed in Section 7.2, it is recommended to avoid different As documented in Section 7.2, it is RECOMMENDED to avoid different
views. If network administrators chose to implement multiple views, views. If network administrators choose to implement multiple views,
impacts on devices' resolution should be evaluated. impacts on devices' resolution SHOULD be evaluated.
A consequence the DNS(SEC) Homenet Zone is expected to be the exact As a consequence, the Homenet Zone is expected to be an exact copy of
copy of the DNS(SEC) Public Zone. As a result, services that are not the Public Homenet Zone. As a result, services that are not expected
expected to be published on the Internet should not be part of the to be published on the Internet SHOULD NOT be part of the Homenet
DNS(SEC) Homenet Zone, local-scope address should not be part of the Zone, local-scope addresses SHOULD NOT be part of the Homenet Zone,
DNS(SEC) Homenet Zone, and when possible, the CPE should sign the and when possible, the CPE SHOULD sign the Homenet Zone.
DNS(SEC) Homenet Zone.
The DNS(SEC) Homenet Zone is expected to host public information. It The Homenet Zone is expected to host public information only. It is
is not to the DNS service to define local home networks boundaries. not the scope of the DNS service to define local home network
Instead, local scope information is expected to be provided to the boundaries. Instead, local scope information is expected to be
home network using local scope naming services. mDNS [RFC6762] DNS-SD provided to the home network using local scope naming services. mDNS
[RFC6763] are one of these services. Currently mDNS is limited to a [RFC6762] DNS-SD [RFC6763] are two examples of these services.
single link network. However, future protocols are expected to Currently mDNS is limited to a single link network. However, future
leverage this constraint as pointed out in protocols are expected to leverage this constraint as pointed out in
[I-D.ietf-dnssd-requirements]. [I-D.ietf-dnssd-requirements].
8. Reverse Zone 8. Homenet Reverse Zone
Most of the description considered the DNS Homenet Zone as the non- This section is focused on the Homenet Reverse Zone.
Reverse Zone. This section is focused on the Reverse Zone.
First, all considerations for the DNS Homenet Zone apply to the Firstly, all considerations for the Homenet Zone apply to the Homenet
Reverse Homenet Zone. The main difference between the Reverse DNS Reverse Zone. The main difference between the Homenet Reverse Zone
Homenet Zone and the DNS Homenet Zone is that the parent zone of the and the Homenet Zone is that the parent zone of the Homenet Reverse
Reverse Homenet Zone is most likely managed by the ISP. As the ISP Zone is most likely managed by the ISP. As the ISP also provides the
also provides the IP prefix to the CPE, it may be able to IP prefix to the CPE, it may be able to authenticate the CPE using
authenticate the CPE. If the Reverse Public Authoritative Name mechanisms outside the scope of this document e.g. the physical
Server Set is managed by the ISP, credentials to authenticate the CPE attachment point to the ISP network. If the Reverse Synchronization
for the zone synchronization may be set automatically and Server is managed by the ISP, credentials to authenticate the CPE for
transparently to the end user. the zone synchronization may be set automatically and transparently
[I-D.ietf-homenet-naming-architecture-dhc-options] describes how to the end user. [I-D.ietf-homenet-naming-architecture-dhc-options]
automatic configuration may be performed. describes how automatic configuration may be performed.
With IPv6, the domain space for IP address is so large, that reverse With IPv6, the domain space for IP addresses is so large that reverse
zone may be confronted to a scalability issue. How to 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 the [I-D.howard-dnsop-ip6rdns] provides guidance on how to address
scalability issue. scalability issues.
9. Renumbering 9. 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 Public Authoritative Name Server Set which acts as a server or the Synchronization Server. Both types of renumbering are
secondary server. Both types of renumbering also designated as discussed i.e. "make-before-break" and "break-before-make".
"make-before-break" or "break-before-make" are discussed.
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 become familiar with them. in [RFC7010] and the reader is expected to be familiar with them
before reading this section.
9.1. Hidden Primary 9.1. 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, it occurs as the whole home network is renumbered. In most cases, this occurs because the whole home
being renumbered. As a result, the DNS(SEC) Homenet Zone will also network is being renumbered. As a result, the Homenet Zone will also
be updated. Although the new and old IP addresses may be stored in be updated. Although the new and old IP addresses may be stored in
the DNS(SEC) Homenet Zone, we recommend that only the newly reachable the Homenet Zone, we recommend that only the newly reachable IP
IP addresses be mentioned. 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 DNS when it is not reachable anymore. Let for example TTL be the TTL
TTL associate to a RRset of the Homenet Zone, it may be cache during associated with a RRset of the Homenet Zone, it may be cached for TTL
TTL seconds. Let T_NEW be the time the new IP address replaces the seconds. Let T_NEW be the time the new IP address replaces the old
old IP address in the DNS, and T_OLD_UNREACHABLE the time the old IP IP address in the Homenet Zone, and T_OLD_UNREACHABLE the time the
is not reachable anymore. In the case of the make-before-break, old IP is not reachable anymore. In the case of the make-before-
seamless reachability is provided as long as T_OLD_UNREACHABLE - break, seamless reachability is provided as long as T_OLD_UNREACHABLE
T_NEW > 2 * TTL. If this is not satisfied, then devices associated - T_NEW > 2 * TTL. If this is not satisfied, then devices associated
to the old IP address in the home network may become unreachable for with the old IP address in the home network may become unreachable
2 * TTL - (T_OLD_UNREACHABLE - T_NEW). In the case of a break- for 2 * TTL - (T_OLD_UNREACHABLE - T_NEW). In the case of a break-
before-make, T_OLD_UNREACHABLE = T_NEW, and the device may become non before-make, T_OLD_UNREACHABLE = T_NEW, and the device may become
reachable up to 2 * TTL. unreachable up to 2 * TTL.
Once the DNS(SEC) Homenet Zone file has been updated on the Hidden Once the Homenet Zone file has been updated on the Hidden Primary,
Primary, the Hidden Primary needs to inform the Public Authoritative the Hidden Primary needs to inform the Outsourcing Infrastructure
Naming Server Set that the DNS(SEC) Homenet Zone has been updated and that the Homenet Zone has been updated and that the IP address to use
that the IP address to use to retrieve the updated zone has also been to retrieve the updated zone has also been updated. Both
updated. Both information are updated using the regular DNS notifications are performed using regular DNS exchanges. Mechanisms
exchanges. More specifically, mechanisms to update a IP address to update an IP address provided by lower layers with protocols like
provided by lower layers with for protocols like SCTP [RFC4960], SCTP [RFC4960], MOBIKE [RFC4555] are not considered in this document.
MOBIKE [RFC4555] are not considered in this document.
The Hidden Primary informs the Public Authoritative Name Server Set The Hidden Primary SHOULD inform the Synchronization Server that the
the DNS(SEC) Homenet Zone has been updated by sending a NOTIFY Homenet Zone has been updated by sending a NOTIFY payload with the
payload with the new IP address. In addition, this NOTIFY payload is new IP address. In addition, this NOTIFY payload SHOULD be
authenticated using SIG(0) or TSIG. When the Public Authoritative authenticated using SIG(0) or TSIG. When the Synchronization Server
Name Server Set receives the NOTIFY payload, it MUST authenticate it. receives the NOTIFY payload, it MUST authenticate it. Note that the
Note that the cryptographic key used for the authentication should be cryptographic key used for the authentication SHOULD be indexed by
indexed by the Homenet Domain Name contained in the NOTIFY payload as the Registered Homenet Domain contained in the NOTIFY payload as well
well as the RRSIG. In other words, the IP address should not be used as the RRSIG. In other words, the IP address SHOULD NOT be used as
as an index. If authentication succeeds, the Public Authoritative an index. If authentication succeeds, the Synchronization Server
Name Server Set MUST also notice the IP address has been modified and MUST also notice the IP address has been modified and perform a
perform a reachability check before updating its primary reachability check before updating its primary configuration. The
configuration. The routability check is performed by sending a SOA routability check MAY performed by sending a SOA request to the
request to the Hidden Primary using the source IP address of the Hidden Primary using the source IP address of the NOTIFY. This
NOTIFY. This exchange is also secured, and if an authenticated exchange is also secured, and if an authenticated response is
response is received from the Hidden Primary with the new IP address, received from the Hidden Primary with the new IP address, the
the Public Authoritative Name Server Set updates its configuration Synchronization Server SHOULD update its configuration file and
file and retrieve the DNS(SEC) Homenet Zone using an AXFR or a IXFR retrieve the Homenet Zone using an AXFR or a IXFR exchange.
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 9.2. Section 9.2.
9.2. Public Authoritative Name Server Set 9.2. Synchronization Server
Renumbering of the Public Authoritative Name Server Set results in Renumbering of the Synchronization Server results in the
the Public Authoritative Name Server Set to change its IP address. Synchronization Server changing its IP address. The Synchronization
The Public Authoritative Name Server Set is a secondary, so its Server is a secondary, so its renumbering does not impact the Homenet
renumbering does not impact the DNS(SEC) Homenet Zone. In fact, Zone. In fact, exchanges to the Synchronization Server are
exchanges to the Public Authoritative Name Server Set are restricted restricted to the Homenet Zone synchronization. In our case, the
to the DNS(SEC) Homenet Zone synchronization. In our case, the Hidden Primary MUST be able to send NOTIFY payloads to the
Hidden Primary MUST be able to send NOTIFY payloads to the Public Synchronization Server.
Authoritative Name Server Set.
If the Public Authoritative Name Server Set is configured in Hidden If the Synchronization Server is configured in the Hidden Primary
Primary configuration file with a FQDN, then the update of the IP configuration file using a FQDN, then the update of the IP address is
address is performed by the DNS(SEC). More specifically, before performed by DNS. More specifically, before sending the NOTIFY, the
sending the NOTIFY, the Hidden Primary performs a DNS(SEC) resolution Hidden Primary performs a DNS resolution to retrieve the IP address
to retrieve the IP address of the secondary. of the secondary.
As described in Section 9.1, the Public Authoritative Name Server Set As described in Section 9.1, the Synchronization Server DNS
DNS information should be coherent with the IP plane. Let TTL be the information SHOULD be coherent with the IP plane. Let TTL be the TTL
TTL associated to the Public Authoritative Name Server Set FQDN, associated with the Synchronization Server FQDN, T_NEW the time the
T_NEW the time the new IP address replaces the old one and new IP address replaces the old one and T_OLD_UNREACHABLE the time
T_OLD_UNREACHABLE the time the Public Authoritative Name Server Set the Synchronization Server is not reachable anymore with its old IP
is not reachable anymore with its old IP address. Seamless address. Seamless reachability is provided as long as
reachability is provided as long as T_OLD_UNREACHABLE - T_NEW > 2 * T_OLD_UNREACHABLE - T_NEW > 2 * TTL. If this condition is not met,
TTL. If this condition is not met, the Public Authoritative Name the Synchronization Server may be unreachable during 2 * TTL -
Server Set may be unreachable during 2 * TTL - (T_OLD_UNREACHABLE - (T_OLD_UNREACHABLE - T_NEW). In the case of a break-before-make,
T_NEW). In the case of a break-before-make, T_OLD_UNREACHABLE = T_OLD_UNREACHABLE = T_NEW, and it may become unreachable up to 2 *
T_NEW, and it may become non reachable up to 2 * TTL. 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. Such scenarios internal interface that is not designated by a FQDN, and to avoid
are considered as out of scope in the case of home networks. potential bootstrap problems. Such scenarios are considered as out
of scope in the case of home networks.
10. Privacy Considerations 10. Privacy Considerations
Outsourcing the DNS Authoritative service from the CPE to a third Outsourcing the DNS Authoritative service from the CPE to a third
entity comes with a few privacy related concerns. party raises a few privacy related concerns.
First the DNS Homenet Zone contains a full description of the The Homenet Zone contains a full description of the services hosted
services hosted in the network. These services may not be expected in the network. These services may not be expected to be publicly
to be publicly shared although their names remains accessible though shared although their names remain accessible through the Internet.
the Internet. Even though DNS makes information public, the DNS does Even though DNS makes information public, the DNS does not expect to
not expect to make the complete list of service public. In fact, make the complete list of services public. In fact, making
making information public still requires the key (or FQDN) of each information public still requires the key (or FQDN) of each service
service to be known by the resolver in order to retrieve information to be known by the resolver in order to retrieve information about
of the services. More specifically, making mywebsite.example.com the services. More specifically, making mywebsite.example.com public
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. existence web site. However, an attacker may walk the reverse DNS
zone, or use other reconnaissance techniques to learn this
information as described in [I-D.ietf-opsec-ipv6-host-scanning].
In order to prevent the complete DN(SEC) Homenet Zone to be published In order to prevent the complete Homenet Zone being published on the
on the Internet, one should prevent AXFR queries on the Public Internet, AXFR queries SHOULD be blocked on the Public Authoritative
Authoritative Primaries. Similarly, to avoid zone-walking one should Server(s). Similarly, to avoid zone-walking NSEC3 [RFC5155] SHOULD
prefer NSEC3 [RFC5155] over NSEC [RFC4034]. be preferred over NSEC [RFC4034].
When the DNS Homenet Zone is outsourced the end user must be aware When the Homenet Zone is outsourced, the end user should be aware
that it provides a complete description of the services available on that it provides a complete description of the services available on
the home network. More specifically, names usually provides a clear the home network. More specifically, names usually provides a clear
indication of the service and eventually the device, by as the DNS indication of the service and possibly even the device type, and as
Homenet Zone contains the IP addresses associated to the service, the Homenet Zone contains the IP addresses associated with the
they limit the scope of the scan. service, they also limit the scope of the scan space.
In addition to the DNS Homenet Zone, the third party can also monitor In addition to the Homenet Zone, the third party can also monitor the
the traffic associated to the DNS Homenet Zone. This traffic may traffic associated with the Homenet Zone. This traffic may provide
provide indication of the services you use, how and when you use an indication of the services an end user accesses, plus how and when
these services. Although, cache may alter this information inside they use these services. Although, caching may obfuscate this
the home network, it is likely that outside your home network this information inside the home network, it is likely that outside your
information will not be cached. home network this information will not be cached.
11. Security Considerations 11. Security Considerations
The Homenet Naming Architecture described in this document solves The Homenet Naming Architecture described in this document solves
exposing the CPE's DNS service as a DoS attack vector. exposing the CPE's DNS service as a DoS attack vector.
11.1. Names are less secure than IP addresses 11.1. Names are less secure than IP addresses
This document describes how an End User can make his services and This document describes how an end user can make their services and
devices from his home network reachable on the Internet with Names devices from his home network reachable on the Internet by using
rather than IP addresses. This exposes the home network to attackers names rather than IP addresses. This exposes the home network to
since names are expected to provide less randomness than IP attackers, since names are expected to include less entropy than IP
addresses. The naming delegation protects the End User's privacy by addresses. In fact, with IP addresses, the Interface Identifier is
not providing the complete zone of the home network to the ISP. 64 bits long leading to up to 2^64 possibilities for a given
However, using the DNS with names for the home network exposes the subnetwork. This is not to mention that the subnet prefix is also of
home network and its components to dictionary attacks. In fact, with 64 bits long, thus providing up to 2^64 possibilities. On the other
IP addresses, the Interface Identifier is 64 bit length leading to hand, names used either for the home network domain or for the
2^64 possibilities for a given subnetwork. This is not to mention devices present less entropy (livebox, router, printer, nicolas,
that the subnet prefix is also of 64 bit length, thus providing jennifer, ...) and thus potentially exposes the devices to dictionary
another 2^64 possibilities. On the other hand, names used either for attacks.
the home network domain or for the devices present less randomness
(livebox, router, printer, nicolas, jennifer, ...) and thus exposes
the devices to dictionary attacks.
11.2. Names are less volatile than IP addresses 11.2. 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 the same However, home networks are not expected to be assigned a time
Prefix over time. As a result observing IP addresses provides some invariant prefix by ISPs. As a result, observing IP addresses only
ephemeral information about who is accessing the service. On the provides some ephemeral information about who is accessing the
other hand, Names are not expected to be as volatile as IP addresses. service. On the other hand, names are not expected to be as volatile
As a result, logging Names, over time, may be more valuable that as IP addresses. As a result, logging names over time may be more
logging IP addresses, especially to profile End User's valuable than logging IP addresses, especially to profile an end
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 we recommend that End Users may choose to respond or not that reason end users may choose not to respond to PTR DNS queries
to PTR DNS queries and may return a NXDOMAIN response. and MAY instead return a NXDOMAIN response.
11.3. DNS Reflection Attacks 11.3. DNS Reflection Attacks
An attacker uses a reflection attack when it sends traffic to an An attacker performs a reflection attack when it sends traffic to one
intermediary node that in turn sends back some traffic to the victim. or more intermediary nodes (reflectors), that in turn send back
Motivations for using an intermediary node might be anonymity of the response traffic to the victim. Motivations for using an
attacker as wells as amplification of the traffic. Typically, when intermediary node might be anonymity of the attacker, as well as
the intermediary node is a DNSSEC server, the attacker sends a DNSSEC amplification of the traffic. Typically, when the intermediary node
query and the victim is likely to receive a DNSSEC response. This is a DNSSEC server, the attacker sends a DNSSEC query and the victim
section analyzes how the different components may be involved in a is likely to receive a DNSSEC response. This section analyzes how
the different components may be involved as a reflector in a
reflection attack. Section 11.3.1 considers the Hidden Primary, reflection attack. Section 11.3.1 considers the Hidden Primary,
Section 11.3.2 the Public Authoritative Name Server Set, and Section 11.3.2 the Synchronization Server, and Section 11.3.3 the
Section 11.3.3 the Public Authoritative Primary. Public Authoritative Server(s).
11.3.1. Reflection Attack involving the Hidden Primary 11.3.1. Reflection Attack involving the Hidden Primary
With the current architecture, the Hidden Primary is only expected to With the specified architecture, the Hidden Primary is only expected
receive DNS queries of type SOA, AXFR or IXFR. This section analyzes to receive DNS queries of type SOA, AXFR or IXFR. This section
how these DNS queries may be used by an attacker to perform a analyzes how these DNS queries may be used by an attacker to perform
reflection attack. a reflection attack.
At first, DNS queries of type AXFR and IXFR uses TCP and as such a DNS queries of type AXFR and IXFR use TCP and as such are less
less subject to reflection attacks. This makes SOA query the only subject to reflection attacks. This makes SOA queries the only
remaining vector of attacks for reflection based on UDP. remaining practical vector of attacks for reflection attacks, based
on UDP.
Firstly, SOA queries are not associated with a large amplification SOA queries are not associated with a large amplification factor
factor compared to queries of type "ANY" or to query of non existing compared to queries of type "ANY" or to query of non existing FQDNs.
FQDNs. This reduces the probability a DNS query of type SOA is This reduces the probability a DNS query of type SOA will be involved
involved in a DDoS attack. In addition, SOA queries are expected to in a DDoS attack.
follow a very specific pattern which makes rate limiting techniques
an efficient way to limit such attacks, with a limited impact on the
naming service of the home network.
This paragraph analyzes how a Hidden Primary could mitigate a flood SOA queries are expected to follow a very specific pattern, which
of SOA requests. Motivations for such flood might be a reflection makes rate limiting techniques an efficient way to limit such
attack, but could be also an attack performed against the Hidden attacks, and associated impact on the naming service of the home
Primary for resource exhaustion. At first, the Hidden Primary only network.
expects traffic from the Public Authoritative Name Server Set that is
its associated secondary. Even though secondary servers may be
renumbered, as exposed in Section 9, the Hidden Primary is likely to
perform a DNSSEC resolution and find out the associated secondary's
IP addresses in use. As a result, the Hidden Primary is likely to
limit the origin of its incoming traffic based on the origin IP
address.
With filtering rules base on the IP address, SOA flooding attacks are Motivations for such a flood might be a reflection attack, but could
also be a resource exhaustion attack performed against the Hidden
Primary. The Hidden Primary only expects to exchange traffic with
the Synchronization Server, that is its associated secondary. Even
though secondary servers may be renumbered as mentioned in Section 9,
the Hidden Primary is likely to perform a DNSSEC resolution and find
out the associated secondary's IP addresses in use. As a result, the
Hidden Primary is likely to limit the origin of its incoming traffic
based on the origin IP address.
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 CPE hosting the Hidden Primary. On the other hand, mitigation by the CPE hosting the Hidden Primary. On the other hand, mitigation
should be appropriately done, 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 Public Authoritative Name Server Set to send The main reason for the Synchronization Server sending a SOA query is
a SOA query is to update the SOA RRset after the TTL expires, to to update the SOA RRset after the TTL expires, to check the serial
check serial number upon the receipt of a NOTIFY query from the number upon the receipt of a NOTIFY query from the Hidden Primary, or
Hidden Primary or to re-send the SOA request when the response has to re-send the SOA request when the response has not been received.
not been received. When a flood of SOA queries is received by the When a flood of SOA queries is received by the Hidden Primary, the
Hidden Primary, the Hidden Primary can assume it is involved in an Hidden Primary may assume it is involved in an attack.
attack. There are a few legitimate time slot the secondary is
expected to send a SOA query. These times may be specific times like
T_NOTIFY the emission of a NOTIFY query, T_SOA + 2/3 TTL, T_SOA +
TTL, T_SOA + T_REFRESH where TTL designates the SOA TTL value,
T_REFRESH the refresh time defined in the SOA RRset, and T_SOA the
last time the SOA has been queried. Outside a few minutes following
these specific time, the probability the CPE discard a legitimate SOA
query is very low. Within these time slots, the probability the
secondary may have its legitimate query rejected is higher. If a
legitimate SOA is discarded, the secondary will re-send SOA query
every "retry time" second until "expire time" seconds occurs, where
"retry time" and "expire time" have been defined in the SOA.
As a result, it is recommended to set rate limiting policies to There are few legitimate time slots when the secondary is expected to
preserve the CPE resource. If a flood lasts more than the expired send a SOA query. Suppose T_NOTIFY is the time a NOTIFY is sent by
time defined by the SOA, it is recommended to re-initiate a 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
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 +
T_REFRESH., and. Outside a few minutes following these specific time
slots, the probability that the CPE discards a legitimate SOA query
is very low. Within these time slots, the probability the secondary
may have its legitimate query rejected is higher. If a legitimate
SOA is discarded, the secondary will re-send SOA query every "retry
time" second until "expire time" seconds occurs, where "retry time"
and "expire time" have been defined in the SOA.
As a result, it is RECOMMENDED to set rate limiting policies to
protect CPE resources. If a flood lasts more than the expired time
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.
11.3.2. Reflection Attacks involving the Public Authoritative Name 11.3.2. Reflection Attacks involving the Synchronization Server
Server Set
The Public Authoritative Name Server Set acts as a secondary toward The Synchronization Server acts as a secondary coupled with the
the Hidden Primary. The secondary expects to receive NOTIFY query, Hidden Primary. The secondary expects to receive NOTIFY query, SOA
SOA responses, AXFR and IXFR responses from the Hidden Primary. responses, AXFR and IXFR responses from the Hidden Primary.
Sending NOTIFY query to the secondary generates a NOTIFY response as Sending a NOTIFY query to the secondary generates a NOTIFY response
well as an SOA query to the Hidden Primary. As mentioned in as well as initiating an SOA query exchange from the secondary to the
[RFC1996], this is a "known benign denial of service attack". As a Hidden Primary. As mentioned in [RFC1996], this is a known "benign
result, the Public Authoritative Name Server Set should enforce rate denial of service attack". As a result, the Synchronization Server
limiting on the SOA queries and NOTIFY responses that are sent to the SHOULD enforce rate limiting on sending SOA queries and NOTIFY
Hidden Primary. Most likely, when the secondary is flooded with responses to the Hidden Primary. Most likely, when the secondary is
valid and signed NOTIFY queries it is under a replay attack which is flooded with valid and signed NOTIFY queries, it is under a replay
discussed in Section 11.5. The key thing here is that the secondary attack which is discussed in Section 11.5. The key thing here is
is likely to be designed to address much traffic than the Hidden that the secondary is likely to be designed to be able to process
Primary hosted on a CPE. much more traffic than the Hidden Primary hosted on a CPE.
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
may not proceed to IP filtering based on the IP address. 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 makes filtering rules based on IP harder to set. At Primaries which make filtering rules based on IP harder to set. The
last, 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 may be easily detected as a predictable. However, a flood of NOTIFY messages may be easily
NOTIFY for a given DNS Homenet Zone is expected to have a very detected, as a NOTIFY originated from a given Homenet Zone is
limited number of different IP addresses even though renumbering expected to have a very limited number of unique source IP addresses,
occurs. As a result, the secondary, can rate limit incoming NOTIFY even when renumbering is occurring. As a result, the secondary, MAY
queries. rate limit incoming NOTIFY queries.
It is recommended the Hidden Primary sends NOTIFY as long as the zone On the Hidden Primary side, it is recommended that the Hidden Primary
has not been updated by the secondary. Multiple SOA queries may sends a NOTIFY as long as the zone has not been updated by the
indicate the secondary is under attack. secondary. Multiple SOA queries may indicate the secondary is under
attack.
11.3.3. Reflection Attacks involving the Public Authoritative Primary 11.3.3. Reflection Attacks involving the Public Authoritative Servers
The Public Authoritative Primary implication of reflection attacks is Reflection attacks involving the Public Authoritative Server(s) are
similar as any public authoritative server. These is not specific to similar to attacks on any Outsourcing Infrastructure. This is not
the architecture described in this document, and thus considered as specific to the architecture described in this document, and thus are
out of scope. considered as out of scope.
In fact, one of the motivation of the architecture described in this In fact, one motivation of the architecture described in this
document was to expose the Public Authoritative Primary to attacks document is to expose the Public Authoritative Server(s) to attacks
instead of the CPE. instead of the CPE, as it is believed that the Public Authoritative
Server(s) will be better able to defend itself.
11.4. Flooding Attack 11.4. 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 or CPU for example. the resource can be bandwidth, memory, or CPU for example.
One of the goal of the architecture described in the document is to One goal of the architecture described in this document is to limit
limit the surface of attack for the CPE. This is done, by the surface of attack on the CPE. This is done by outsourcing the
outsourcing the DNS service to the Public Authoritative Primaries. DNS service to the Public Authoritative Server(s). By doing so, the
By doing so, the CPE limits its DNS interactions between the Hidden CPE limits its DNS interactions between the Hidden Primary and the
Primary and the Public Authoritative Name Server Set. This limits the Synchronization Server. This limits the number of entities the CPE
number of entity the CPE interacts with as well as the scope of DNS interacts with as well as the scope of DNS exchanges - NOTIFY, SOA,
exchanges - basically 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
CPE and the Public Authoritative Name Server Set, enables to detect CPE and the Synchronization Server, enables detection of illegitimate
illegitimate DNS queries, and take appropriated actions - like DNS queries, so appropriate action may be taken - like dropping the
dropping the queries. If signatures are validated, then most likely, queries. If signatures are validated, then most likely, the CPE is
the CPE is under a replay attack, as detailed in Section 11.5 under a replay attack, as detailed in Section 11.5
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.
11.5. Replay Attack 11.5. Replay Attack
Replay attacks consist in sending a message that has already been Replay attacks consist of an attacker either resending or delaying a
sent. As the Hidden Primary and the Public Authoritative Name Server legitimate message that has been sent by an authorized user or
Set use an authenticated channel, replay attacks are mostly expected process. As the Hidden Primary and the Synchronization Server use an
to used over forged DNS queries in order to provide valid traffic. authenticated channel, replay attacks are mostly expected to use
forged DNS queries in order to provide valid traffic.
On an attacker points of view, using a correctly authenticated DNS From the perspective of an attacker, using a correctly authenticated
query, may not be detected as an attack, and thus may generate the DNS query may not be detected as an attack and thus may generate a
corresponding response. Generating and sending a response consumes response. Generating and sending a response consumes more resources
more resources then dropping the query and thus could be used for than either dropping the query by the defender, or generating the
resource exhaustion attacks. In addition, as the authentication is query by the attacker, and thus could be used for resource exhaustion
performed at the DNS layer, the IP address could be impersonated in attacks. In addition, as the authentication is performed at the DNS
order to perform a reflection attack. layer, the source IP address could be impersonated in order to
perform a reflection attack.
Section 11.3 details how to mitigate reflection attacks and Section 11.3 details how to mitigate reflection attacks and
Section 11.4 details how to mitigate resource exhaustion. Both Section 11.4 details how to mitigate resource exhaustion. Both
section assumes 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 address replay attack as a way to limit the surface of these section suggests a way to limit the attack surface of replay attacks.
attacks.
As SIG(0) and TSIG uses 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
loose time synchronization of the devices and short live time for the possibly loose time synchronization between devices and the valid
message. As a result, better time synchronization policies could lifetime of the message. As a result, better time synchronization
reduce the time window of the attack. policies could reduce the time window of the attack.
12. IANA Considerations 12. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
13. Acknowledgment 13. 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
CPE and low power devices; Olafur Gudmundsson for clarifying DNSSEC CPE 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 feed backs 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 CPE; Ray Hunter, outsourcing the zone signing operation outside the CPE; Mark Andrew
Mark Andrew and Peter Koch for clarifying the renumbering. and Peter Koch for clarifying the renumbering.
14. References 14. References
14.1. Normative References 14.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", [RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987. STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
skipping to change at page 28, line 19 skipping to change at page 28, line 19
NCACHE)", RFC 2308, March 1998. NCACHE)", RFC 2308, March 1998.
[RFC2845] Vixie, P., Gudmundsson, O., Eastlake, D., and B. [RFC2845] Vixie, P., Gudmundsson, O., Eastlake, D., and B.
Wellington, "Secret Key Transaction Authentication for DNS Wellington, "Secret Key Transaction Authentication for DNS
(TSIG)", RFC 2845, May 2000. (TSIG)", RFC 2845, May 2000.
[RFC2930] Eastlake, D., "Secret Key Establishment for DNS (TKEY [RFC2930] Eastlake, D., "Secret Key Establishment for DNS (TKEY
RR)", RFC 2930, September 2000. RR)", RFC 2930, September 2000.
[RFC2931] Eastlake, D., "DNS Request and Transaction Signatures ( [RFC2931] Eastlake, D., "DNS Request and Transaction Signatures (
SIG(0)s)", RFC 2931, September 2000. SIG(0)s )", RFC 2931, September 2000.
[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, March 2005. RFC 4034, March 2005.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the [RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005. Internet Protocol", RFC 4301, December 2005.
[RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol [RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, June 2006. (MOBIKE)", RFC 4555, June 2006.
skipping to change at page 29, line 27 skipping to change at page 29, line 27
progress), June 2014. progress), June 2014.
[I-D.ietf-dnssd-requirements] [I-D.ietf-dnssd-requirements]
Lynn, K., Cheshire, S., Blanchet, M., and D. Migault, Lynn, K., Cheshire, S., Blanchet, M., and D. Migault,
"Requirements for Scalable DNS-SD/mDNS Extensions", draft- "Requirements for Scalable DNS-SD/mDNS Extensions", draft-
ietf-dnssd-requirements-06 (work in progress), March 2015. ietf-dnssd-requirements-06 (work in progress), March 2015.
[I-D.ietf-homenet-naming-architecture-dhc-options] [I-D.ietf-homenet-naming-architecture-dhc-options]
Migault, D., Cloetens, W., Griffiths, C., and R. Weber, Migault, D., Cloetens, W., Griffiths, C., and R. Weber,
"DHCP Options for Homenet Naming Architecture", draft- "DHCP Options for Homenet Naming Architecture", draft-
ietf-homenet-naming-architecture-dhc-options-01 (work in ietf-homenet-naming-architecture-dhc-options-02 (work in
progress), February 2015. progress), May 2015.
[I-D.ietf-opsec-ipv6-host-scanning]
Gont, F. and T. Chown, "Network Reconnaissance in IPv6
Networks", draft-ietf-opsec-ipv6-host-scanning-07 (work in
progress), April 2015.
[RFC1033] Lottor, M., "Domain administrators operations guide", RFC [RFC1033] Lottor, M., "Domain administrators operations guide", RFC
1033, November 1987. 1033, November 1987.
[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for [RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
Renumbering an IPv6 Network without a Flag Day", RFC 4192, Renumbering an IPv6 Network without a Flag Day", RFC 4192,
September 2005. September 2005.
[RFC7010] Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W. [RFC7010] Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W.
George, "IPv6 Site Renumbering Gap Analysis", RFC 7010, George, "IPv6 Site Renumbering Gap Analysis", RFC 7010,
skipping to change at page 30, line 9 skipping to change at page 30, line 9
2014. 2014.
[RFC7368] Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil, [RFC7368] Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil,
"IPv6 Home Networking Architecture Principles", RFC 7368, "IPv6 Home Networking Architecture Principles", RFC 7368,
October 2014. October 2014.
Appendix A. Document Change Log Appendix A. Document Change Log
[RFC Editor: This section is to be removed before publication] [RFC Editor: This section is to be removed before publication]
-07:
Ray Hunter is added as a co-author.
-06: -06:
Ray Hunter is added in acknowledgment. Ray Hunter is added in acknowledgment.
Adding Renumbering section with comments from Dallas meeting Adding Renumbering section with comments from Dallas meeting
Replacing Master / Primary - Slave / Secondary Replacing Master / Primary - Slave / Secondary
Security Consideration has been updated with Reflection attacks, Security Consideration has been updated with Reflection attacks,
flooding attacks, and replay attacks. flooding attacks, and replay attacks.
-05: -05:
*Clarifying on handling different views: *Clarifying on handling different views:
- 1: How the CPE may be involved in the resolution and responds - 1: How the CPE may be involved in the resolution and responds
without necessarily requesting the Public Primaries (and without necessarily requesting the Public Authoritative
eventually the Hidden Primary) Server(s) (and eventually the Hidden Primary)
- 2: How to handle local scope resolution that is link-local, site- - 2: How to handle local scope resolution that is link-local, site-
local and NAT IP addresses as well as Private domain names that local and NAT IP addresses as well as Private domain names that
the administrator does not want to publish outside the home the administrator does not want to publish outside the home
network. network.
Adding a Privacy Considerations Section Adding a Privacy Considerations Section
Clarification on pro/cons outsourcing zone-signing Clarification on pro/cons outsourcing zone-signing
skipping to change at page 31, line 20 skipping to change at page 31, line 23
*Adding SIG(0) as a mechanism for authenticating the servers *Adding SIG(0) as a mechanism for authenticating the servers
*Goals clarification: the architecture described in the document 1) *Goals clarification: the architecture described in the document 1)
does not describe new protocols, and 2) can be adapted to specific does not describe new protocols, and 2) can be adapted to specific
cases for advance users. cases for advance users.
-02: -02:
*remove interfaces: "Public Authoritative Server Naming Interface" is *remove interfaces: "Public Authoritative Server Naming Interface" is
replaced by "Public Authoritative Primary(ies)". "Public replaced by "Public Authoritative Server(s)y(ies)". "Public
Authoritative Server Management Interface" is replaced by "Public Authoritative Server Management Interface" is replaced by
Authoritative Name Server Set". "Synchronization Server".
-01.3: -01.3:
*remove the authoritative / resolver services of the CPE. *remove the authoritative / resolver services of the CPE.
Implementation dependent Implementation dependent
*remove interactions with mdns and dhcp. Implementation dependent. *remove interactions with mdns and dhcp. Implementation dependent.
*remove considerations on low powered devices *remove considerations on low powered devices
skipping to change at page 32, line 24 skipping to change at page 32, line 28
* For next version, address functions of MDNS within Homenet Lan and * For next version, address functions of MDNS within Homenet Lan and
publishing details northbound via Hidden Primary. publishing details northbound via Hidden Primary.
-00: First version published. -00: First version published.
Authors' Addresses Authors' Addresses
Daniel Migault Daniel Migault
Ericsson Ericsson
8400 boulevard Decarie 8400 Boulevard Decarie
Montreal, QC H4P 2N2 Montreal, QC H4P 2N2
Canada Canada
Email: mglt.ietf@gmail.com Phone: +1 (514) 452-2160
Email: daniel.migault@ericsson.com
Wouter Cloetens
SoftAtHome
vaartdijk 3 701
3018 Wijgmaal
Belgium
Email: wouter.cloetens@softathome.com
Chris Griffiths
Dyn
150 Dow Street
Manchester, NH 03101
US
Email: cgriffiths@dyn.com
URI: http://dyn.com
Ralf Weber Ralf Weber
Nominum Nominum
2000 Seaport Blvd #400 2000 Seaport Blvd #400
Redwood City, CA 94063 Redwood City, CA 94063
US US
Email: ralf.weber@nominum.com Email: ralf.weber@nominum.com
URI: http://www.nominum.com URI: http://www.nominum.com
Ray Hunter
Globis Consulting BV
Weegschaalstraat 3
5632CW Eindhoven
The Netherlands
Email: v6ops@globis.net
URI: http://www.globis.net
Chris Griffiths
Email: cgriffiths@gmail.com
Wouter Cloetens
SoftAtHome
vaartdijk 3 701
3018 Wijgmaal
Belgium
Email: wouter.cloetens@softathome.com
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