draft-ietf-homenet-front-end-naming-delegation-01.txt   draft-ietf-homenet-front-end-naming-delegation-02.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 W. Cloetens
Expires: August 20, 2015 SoftAtHome Expires: November 5, 2015 SoftAtHome
C. Griffiths C. Griffiths
Dyn Dyn
R. Weber R. Weber
Nominum Nominum
February 16, 2015 May 4, 2015
Outsourcing Home Network Authoritative Naming Service Outsourcing Home Network Authoritative Naming Service
draft-ietf-homenet-front-end-naming-delegation-01.txt draft-ietf-homenet-front-end-naming-delegation-02.txt
Abstract Abstract
CPEs are designed to provide IP connectivity to home networks. Most CPEs are designed to provide IP connectivity to home networks. Most
CPEs assign IP addresses to the nodes of the home network which makes CPEs assign IP addresses to the nodes of the home network which makes
it a good candidate for hosting the naming service. With IPv6, the it a good candidate for hosting the naming service. With IPv6, the
naming service makes nodes reachable from the home network as well as naming service makes nodes reachable from the home network as well as
from the Internet. from 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. This may expose the CPEs to resource
exhaustion which would make the home network unreachable, and most exhaustion which would make the home network unreachable, and most
probably would also affect the home network inner communications. probably would also affect the home network inner communications.
In addition, DNSSEC management and configuration may not be well In addition, DNSSEC management and configuration may not be well
understood or mastered by regular end users. Misconfiguration may understood or mastered by regular end users. Misconfiguration may
also results in naming service disruption, thus these end users may also result in naming service disruption, thus these end users may
prefer to rely on third party naming providers. prefer to rely on third party naming 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 associates to its home network, and outsources manage the DNS zone associated to its home network, and outsources
the naming service and eventually the DNSSEC management on the the naming service and eventually the DNSSEC management on the
Internet to a third party designated as the Public Authoritative Internet to a third party designated as the Public Authoritative
Servers. 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 August 20, 2015. This Internet-Draft will expire on November 5, 2015.
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.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 33 skipping to change at page 2, line 33
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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 . . . . . . . . . . . . . . . . . . 5
4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 5 4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 6
4.2. Example: DNS(SEC) Homenet Zone . . . . . . . . . . . . . 7 4.2. Example: DNS(SEC) Homenet Zone . . . . . . . . . . . . . 8
4.3. Example: CPE necessary parameters for outsourcing . . . . 9 4.3. Example: CPE necessary parameters for outsourcing . . . . 10
5. Synchronization between CPE and Public Authoritative Servers 10 5. Synchronization between CPE and Public Authoritative Name
5.1. Synchronization with a Hidden Master . . . . . . . . . . 10 Server Sets . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2. Securing Synchronization . . . . . . . . . . . . . . . . 11 5.1. Synchronization with a Hidden Primary . . . . . . . . . . 11
5.3. CPE Security Policies . . . . . . . . . . . . . . . . . . 13 5.2. Securing Synchronization . . . . . . . . . . . . . . . . 12
6. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 13 5.3. CPE Security Policies . . . . . . . . . . . . . . . . . . 14
6.1. Zone Signing . . . . . . . . . . . . . . . . . . . . . . 13 6. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 14
6.2. Secure Delegation . . . . . . . . . . . . . . . . . . . . 15 6.1. Zone Signing . . . . . . . . . . . . . . . . . . . . . . 14
7. Handling Different Views . . . . . . . . . . . . . . . . . . 15 6.2. Secure Delegation . . . . . . . . . . . . . . . . . . . . 16
7.1. Motivations . . . . . . . . . . . . . . . . . . . . . . . 16 7. Handling Different Views . . . . . . . . . . . . . . . . . . 16
7.2. Consequences . . . . . . . . . . . . . . . . . . . . . . 16 7.1. Misleading Reasons for Local Scope DNS Zone . . . . . . . 17
7.3. Guidance and Recommendations . . . . . . . . . . . . . . 17 7.2. Consequences . . . . . . . . . . . . . . . . . . . . . . 17
8. Reverse Zone . . . . . . . . . . . . . . . . . . . . . . . . 17 7.3. Guidance and Recommendations . . . . . . . . . . . . . . 18
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18 8. Reverse Zone . . . . . . . . . . . . . . . . . . . . . . . . 18
10. Security Considerations . . . . . . . . . . . . . . . . . . . 19 9. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 19
10.1. Names are less secure than IP addresses . . . . . . . . 19 9.1. Hidden Primary . . . . . . . . . . . . . . . . . . . . . 19
10.2. Names are less volatile than IP addresses . . . . . . . 19 9.2. Public Authoritative Name Server Set . . . . . . . . . . 21
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 21
12. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 20 11. Security Considerations . . . . . . . . . . . . . . . . . . . 22
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 11.1. Names are less secure than IP addresses . . . . . . . . 22
13.1. Normative References . . . . . . . . . . . . . . . . . . 20 11.2. Names are less volatile than IP addresses . . . . . . . 23
13.2. Informational References . . . . . . . . . . . . . . . . 21 11.3. DNS Reflection Attacks . . . . . . . . . . . . . . . . . 23
Appendix A. Document Change Log . . . . . . . . . . . . . . . . 22 11.3.1. Reflection Attack involving the Hidden Primary . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 11.3.2. Reflection Attacks involving the Public
Authoritative Name Server Set . . . . . . . . . . . 25
11.3.3. Reflection Attacks involving the Public
Authoritative Primary . . . . . . . . . . . . . . . 25
11.4. Flooding Attack . . . . . . . . . . . . . . . . . . . . 26
11.5. Replay Attack . . . . . . . . . . . . . . . . . . . . . 26
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
13. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 27
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
14.1. Normative References . . . . . . . . . . . . . . . . . . 27
14.2. Informational References . . . . . . . . . . . . . . . . 29
Appendix A. Document Change Log . . . . . . . . . . . . . . . . 30
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. To access services
skipping to change at page 3, line 34 skipping to change at page 3, line 46
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 the CPEs a good candidate to manage binding
between names and IP addresses of the nodes. In addition, [RFC7368] between names and IP addresses of the 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 requires that a dedicate device inside the home
network manage bindings between names and IP addresses of the nodes network manage bindings between names and IP addresses of the nodes
and builds the DNS Homenet Zone. All this makes the CPE the natural and builds the DNS Homenet Zone. All this makes the CPE the natural
candidate for setting the DNS(SEC) zone file of the home network. candidate for setting the DNS(SEC) zone file of the home network.
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 the an authoritative but not for heavy traffic. As a result, hosting an authoritative DNS
DNS service on the Internet may expose the home network to resource service on the Internet may expose the home network to resource
exhaustion, which may isolate the home network from the Internet and exhaustion, which may isolate the home network from the Internet and
affect the services hosted by the CPEs, thus affecting the overall affect the services hosted by the CPEs, thus affecting the overall
home network communications. home network communications.
In order to avoid resource exhaustion, this document describes an In order to avoid resource exhaustion, this document describes an
architecture that outsources the authoritative naming service of the architecture that outsources the authoritative naming service of the
home network. More specifically, the DNS(SEC) Homenet Zone built by home network. More specifically, the DNS(SEC) Homenet Zone built by
the CPE is outsourced to Public Authoritative Servers. These servers the CPE is outsourced to Public Authoritative Servers. These servers
publish the corresponding DN(SEC) Public Zone on the Internet. publish the corresponding DN(SEC) Public Zone on the Internet.
Section 4.1 describes the architecture. In order to keep the Section 4.1 describes the architecture. In order to keep the
DNS(SEC) Public Zone up-to-date Section 5 describes how the DNS(SEC) DNS(SEC) Public Zone up-to-date Section 5 describes how the DNS(SEC)
Homenet Zone and the DN(SEC) Public Zone can be synchronized. The Homenet Zone and the DN(SEC) Public Zone can be synchronized. The
proposed architecture aims at deploying DNSSEC and the DNS(SEC) proposed architecture aims at deploying DNSSEC and the DNS(SEC)
Public Zone is expected to be signed with a secure delegation. The Public Zone is expected to be signed with a secure delegation. The
zone signing and secure delegation can be performed either by the CPE zone signing and secure delegation can be performed either by the CPE
or by the Public Authoritative Servers. Section 6 discusses these or by the Public Authoritative Servers. Section 6 discusses these
two alternatives. Section 7 discusses multiple views aspects and two alternatives. Section 7 discusses multiple views aspects and
provide guidance to avoid them. Section 8 discusses the case of the provide guidance to avoid them. Section 8 discusses the case of the
reverse zone. Section 9 and Section 10 respectively discuss privacy reverse zone. Section 9 discusses how renumbering should be handled.
and security considerations when outsourcing the DNS Homenet Zone. Finally, Section 10 and Section 11 respectively discuss privacy and
security considerations when outsourcing the DNS 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 is configured and managed
by the end user. In this document, the CPE MAY also hosts by the end user. In this document, the CPE MAY also host
services such as DHCPv6. This device MAY be provided by the services such as DHCPv6. This device MAY be provided by the
ISP. 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. - DNS Homenet Zone: is the DNS zone associated to the home network.
This zone is set by the CPE and essentially contains the This zone is set by the CPE and essentially contains the
bindings between names and IP addresses of the nodes of the bindings between names and IP addresses of the nodes of the
home network. In this document, the CPE does neither perform home network. In this document, the CPE does neither perform
any DNSSEC management operations such as zone signing nor any DNSSEC management operations such as zone signing nor
provide an authoritative service for the zone. Both are provide an authoritative service for the zone. Both are
delegated to the Public Authoritative Server. The CPE delegated to the Public Authoritative Server. The CPE
synchronizes the DNS Homenet Zone with the Public Authoritative synchronizes the DNS Homenet Zone with the Public Authoritative
Server via a hidden master / slave architecture. The Public Server via a hidden primary / secondary architecture. The
Authoritative Server MAY use specific servers for the Public Authoritative Server MAY use specific servers for the
synchronization of the DNS Homenet Zone: the Public synchronization of the DNS Homenet Zone: the Public
Authoritative Name Server Set as public available name servers Authoritative Name Server Set as public available name servers
for the Registered Homenet Domain. for the Registered Homenet Domain.
- DNS Homenet Reverse Zone: The reverse zone file associated to the - DNS Homenet Reverse Zone: The reverse zone file associated to the
DNS Homenet Zone. DNS Homenet Zone.
- Public Authoritative Server: performs DNSSEC management - Public Authoritative Server: performs DNSSEC management
operations as well as provides the authoritative service for operations as well as provides the authoritative service for
the zone. In this document, the Public Authoritative Server the zone. In this document, the Public Authoritative Server
synchronizes the DNS Homenet Zone with the CPE via a hidden synchronizes the DNS Homenet Zone with the CPE via a hidden
master / slave architecture. The Public Authoritative Server primary / secondary architecture. The Public Authoritative
acts as a slave and MAY use specific servers called Public Server acts as a secondary and MAY use specific servers called
Authoritative Name Server Set. Once the Public Authoritative Public Authoritative Name Server Set. Once the Public
Server synchronizes the DNS Homenet Zone, it signs the zone and Authoritative Server synchronizes the DNS Homenet Zone, it
generates the DNSSEC Public Zone. Then the Public signs the zone and generates the DNSSEC Public Zone. Then the
Authoritative Server hosts the zone as an authoritative server Public Authoritative Server hosts the zone as an authoritative
on the Public Authoritative Master(s). server on the Public Authoritative Primary(ies).
- DNSSEC Public Zone: corresponds to the signed version of the DNS - DNSSEC Public Zone: corresponds to the signed version of the DNS
Homenet Zone. It is hosted by the Public Authoritative Server, Homenet Zone. It is hosted by the Public Authoritative Server,
which is authoritative for this zone, and is reachable on the which is authoritative for this zone, and is reachable on the
Public Authoritative Master(s). Public Authoritative Primary(ies).
- Public Authoritative Master(s): are the visible name server - Public Authoritative Primary(ies): are the visible name server
hosting the DNSSEC Public Zone. End users' resolutions for the hosting the DNSSEC Public Zone. End users' resolutions for the
Homenet Domain are sent to this server, and this server is a Homenet Domain are sent to this server, and this server is a
master for the zone. primary for the zone.
- Public Authoritative Name Server Set: is the server the CPE - Public Authoritative Name Server Set: is the server the CPE
synchronizes the DNS Homenet Zone. It is configured as a slave synchronizes the DNS Homenet Zone. It is configured as a
and the CPE acts as master. The CPE sends information so the secondary and the CPE acts as primary. The CPE sends
DNSSEC zone can be set and served. information so the DNSSEC zone can be set and served.
- Reverse Public Authoritative Master(s): are the visible name - Reverse Public Authoritative Primary(ies): are the visible name
server hosting the DNS Homenet Reverse Zone. End users' server hosting the DNS Homenet Reverse Zone. End users'
resolutions for the Homenet Domain are sent to this server, and resolutions for the Homenet Domain are sent to this server, and
this server is a master for the zone. this server is a primary for the zone.
- Reverse Public Authoritative Name Server Set: is the server the - Reverse Public Authoritative Name Server Set: is the server the
CPE synchronizes the DNS Homenet Reverse Zone. It is CPE synchronizes the DNS Homenet Reverse Zone. It is
configured as a slave and the CPE acts as master. The CPE configured as a secondary and the CPE acts as primary. The CPE
sends information so the DNSSEC zone can be set and served. sends information so the DNSSEC zone can be set and served.
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 Public Authoritative
Master(s). Section 4.1 describes the architecture, Section 4.2 and Primary(ies). Section 4.1 describes the architecture, Section 4.2
Section 4.3 illustrate this architecture and shows how the DNS(SEC) and Section 4.3 illustrate this architecture and shows how the
Homenet Zone should be built by the CPE, as well as lists the DNS(SEC) Homenet Zone should be built by the CPE, as well as lists
necessary parameters the CPE needs to outsource the authoritative the necessary parameters the CPE needs to outsource the authoritative
naming service. These two section are informational and non naming service. These two section 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 DNS(SEC) Homenet Zone
associated to the home network. How the DNS(SEC) Homenet Zone is associated to the home network. How the DNS(SEC) Homenet Zone is
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The Public Authoritative Servers are described in Figure 2. The The Public Authoritative Servers are described in Figure 2. The
Public Authoritative Name Server Set receives the DNS(SEC) Homenet Public Authoritative Name Server Set receives the DNS(SEC) Homenet
Zone as an input. The received zone may be transformed to output the Zone as an input. The received zone may be transformed to output the
DNS(SEC) Public Zone. Various operations may be performed here, DNS(SEC) Public Zone. Various operations may be performed here,
however this document only considers zone signing as potential however this document only considers zone signing as potential
operation. This could occur only when the CPE outsources this operation. This could occur only when the CPE outsources this
operation to the Public Authoritative Name Server Set. On the other operation to the Public Authoritative Name Server Set. On the other
hand, if the CPE signs the DNSSEC Homenet Zone itself, the zone it hand, if the CPE signs the DNSSEC Homenet Zone itself, the zone it
collected by the Public Authoritative Name Server Set and directly collected by the Public Authoritative Name Server Set and directly
transferred to the Public Authoritative Master. Implications of such transferred to the Public Authoritative Primary. Implications of
policy are detailed in Section 6 and Section 7. such policy are detailed in Section 6 and Section 7.
Internet Internet
+--------------------------------------------------------+ +--------------------------------------------------------+
| Public Authoritative Servers | | Public Authoritative Servers |
+--------------------------------------------------------+ +--------------------------------------------------------+
+----------------------+ +----------------------+ +----------------------+ +----------------------+
| | | | | | | |
| Public Authoritative | | Public Authoritative | | Public Authoritative | | Public Authoritative |
| Name Server Set | | Masters | | Name Server Set | | Primaries |
| | | | | | | |
| +------------------+ | X | +------------------+ | | +------------------+ | X | +------------------+ |
| | DNS(SEC) Homenet | | ^ | | DNS(SEC) Public | | | | DNS(SEC) Homenet | | ^ | | DNS(SEC) Public | |
=========>| | Zone | | | | | 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: Public Authoritative Servers Description
4.2. Example: DNS(SEC) Homenet Zone 4.2. Example: DNS(SEC) 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 DNS(SEC) 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 DNS(SEC) Public Zone is
hosted on the Public Authoritative Masters, whereas the DNS(SEC) hosted on the Public Authoritative Primaries, whereas the DNS(SEC)
Homenet Zone is hosted on the CPE. Motivations for keeping these two Homenet Zone is hosted on the CPE. Motivations for keeping these two
zones identical are detailed in Section 7, and this section considers zones identical are detailed in Section 7, and this section considers
that the CPE builds the zone that will be effectively published on that the CPE builds the zone that will be effectively published on
the Public Authoritative Masters. In other words "Homenet to Public the Public Authoritative Primaries. In other words "Homenet to
Zone transformation" is the identity. Public Zone transformation" is the identity.
In that case, the DNS Homenet Zone should configure its Name Server In that case, the DNS Homenet Zone should configure its Name Server
RRset (NS) and Start of Authority (SOA) with the ones associated to RRset (NS) and Start of Authority (SOA) with the ones associated to
the Public Authoritative Masters. This is illustrated in Figure 3. the Public Authoritative Primaries. This is illustrated in Figure 3.
public.masters.example.net is the FQDN of the Public Authoritative public.primary.example.net is the FQDN of the Public Authoritative
Masters, and IP1, IP2, IP3, IP4 are the associated IP addresses. Primaries, 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 different 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 DNS Homenet
Zone. Zone.
$ORIGIN example.com $ORIGIN example.com
$TTL 1h $TTL 1h
@ IN SOA public.masters.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 ; slave refresh 1d ; secondary refresh
2h ; slave retry time in case of a problem 2h ; secondary retry time in case of a problem
4w ; slave 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.masters.example.net A @IP1 public.primary.example.net A @IP1
public.masters.example.net A @IP2 public.primary.example.net A @IP2
public.masters.example.net AAAA @IP3 public.primary.example.net AAAA @IP3
public.masters.example.net AAAA @IP4 public.primary.example.net AAAA @IP4
Figure 3: DNS Homenet Zone Figure 3: DNS 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 Master and the Public Authoritative Name Server Set and Hidden Primary and the Public Authoritative Name Server Set and
published on the DNS Public Authoritative Master. published on the DNS Public Authoritative Primary.
- MNAME: indicates the primary master. In our case the zone is - MNAME: indicates the primary. In our case the zone is published
published on the Public Authoritative Master, and its name MUST on the Public Authoritative Primary, and its name MUST be
be mentioned. If multiple Public Authoritative Masters are mentioned. If multiple Public Authoritative Primaries 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 Master. CPE MUST NOT place 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 to use 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
slaves need to check the master 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 value 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 MAY be long for highly dynamic content.
However, Public Authoritative Masters and the CPE are expected However, Public Authoritative Primaries and the CPE are
to implement NOTIFY [RFC1996]. Then short values MAY increase expected to implement NOTIFY [RFC1996]. Then short values MAY
the bandwidth usage for slaves hosting large number of zones. increase the bandwidth usage for secondaries hosting large
As a result, default values looks fine. number of zones. As a result, default values looks fine.
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. Default value indicated by [RFC1033] is 3600000 about
42 days. In home network architectures, the CPE provides both 42 days. In home network architectures, the CPE provides both
the DNS synchronization and the access to the home network. the DNS synchronization and the access to the home network.
This device MAY be plug / unplugged by the end user without This device MAY be plugged and unplugged by the end user
notification, thus we recommend large period. without notification, thus we recommend large period.
MINIMUM: indicates the minimum TTL. Default value indicated by MINIMUM: indicates the minimum TTL. 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 (1hour) seems more appropriated. be reduced, and 3600 (1 hour) seems more appropriated.
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 Public Authoritative Name Server Set may be defined with the
following parameters. These parameters are necessary to establish a following parameters. These parameters are necessary to establish a
skipping to change at page 9, line 50 skipping to change at page 10, line 43
- 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 Public Server. This MAY depend on the implementation but we
should consider at least IPsec, DTLS and TSIG should consider 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, files for the CPE private keys,
certificates and certification authority should be specified. certificates and certification authority should be specified.
- Public Authoritative Master(s): The FQDN or IP addresses of the - Public Authoritative Primary(ies): The FQDN or IP addresses of
Public Authoritative Master. It MAY correspond to the data the Public Authoritative Primary. It MAY correspond to the
that will be set in the NS RRsets and SOA of the DNS Homenet data that will be set in the NS RRsets and SOA of the DNS
Zone. IP addresses are optional and the FQDN is sufficient. Homenet Zone. IP addresses are optional and the FQDN is
To secure the binding name and IP addresses, a DNSSEC exchange sufficient. To secure the binding name and IP addresses, a
is required. Otherwise, the IP addresses should be entered DNSSEC exchange is required. Otherwise, the IP addresses
manually. should be entered manually.
- Registered Homenet Domain: The domain name the Public - Registered Homenet Domain: The domain name the Public
Authoritative is configured for DNS slave, DNSSEC zone signing Authoritative is configured for DNS secondary, DNSSEC zone
and DNSSEC zone hosting. signing and DNSSEC zone hosting.
Setting the DNS(SEC) Homenet Zone requires the following information. Setting the DNS(SEC) 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 Domain may be provided. This will generate
the creation of multiple DNS Homenet Zones. the creation of multiple DNS Homenet Zones.
- Public Authoritative Server: The Public Authoritative Servers - Public Authoritative Primaries: The public authoritative servers
associated to the Registered Homenet Domain. Multiple Public associated to the Registered Homenet Domain. Multiple public
Authoritative Server may be provided. authoritative server may be provided.
5. Synchronization between CPE and Public Authoritative Servers 5. Synchronization between CPE and Public Authoritative Name Server
Sets
The DNS(SEC) Homenet Reverse Zone and the DNS Homenet Zone can be The DNS(SEC) Homenet Reverse Zone and the DNS Homenet Zone can be
updated either with DNS update [RFC2136] or using a master / slave updated either with DNS update [RFC2136] or using a primary /
synchronization. The master / slave mechanism is preferred as it secondary synchronization. The primary / secondary mechanism is
better scales and avoids DoS attacks: First the master notifies the preferred as it better scales and avoids DoS attacks: First the
slave the zone must be updated, and leaves the slave to proceed to primary notifies the secondary the zone must be updated, and leaves
the update when possible. Then, the NOTIFY message sent by the the secondary to proceed to the update when possible. Then, the
master is a small packet that is less likely to load the slave. At NOTIFY message sent by the primary is a small packet that is less
last, the AXFR query performed by the slave is a small packet sent likely to load the secondary. At last, the AXFR query performed by
over TCP (section 4.2 [RFC5936]) which makes unlikely the slave to the secondary is a small packet sent over TCP (section 4.2 [RFC5936])
perform reflection attacks with a forged NOTIFY. On the other hand, which makes unlikely the secondary to perform reflection attacks with
DNS updates can use UDP, packets require more processing then a a forged NOTIFY. On the other hand, DNS updates can use UDP, packets
NOTIFY, and they do not provide the server the opportunity to post- require more processing then a NOTIFY, and they do not provide the
pone the update. server the opportunity to post-pone the update.
This document recommends the use of a master / slave mechanism This document recommends the use of a primary / secondary mechanism
instead of the use of nsupdates. This section details the master / instead of the use of nsupdates. This section details the primary /
slave mechanism. secondary mechanism.
5.1. Synchronization with a Hidden Master 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 Public
Authoritative Name Server Set can be seen as zone provisioning Authoritative Name Server Set can be seen as zone provisioning
between the CPE (Hidden Master) and the Public Authoritative Name between the CPE (Hidden Primary) and the Public Authoritative Name
Server Set (Slave Server). This can be handled either in band or out Server Set (Secondary Server). This can be handled either in band or
of band. out of band.
The Public Authoritative Name Server Set is configured as a slave for The Public Authoritative Name Server Set is configured as a secondary
the Homenet Domain Name. This slave configuration has been for the 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 Public
Authoritative Servers. In order to set the master/ slave Authoritative Name Server Sets. In order to set the primary/
architecture, the CPE acts as a Hidden Master Server, which is a secondary architecture, the CPE acts as a Hidden Primary Server,
regular Authoritative DNS(SEC) Server listening on the WAN interface. which is a regular Authoritative DNS(SEC) Server listening on the WAN
interface.
The Hidden Master Server is expected to accept SOA [RFC1033], AXFR The Hidden Primary Server is expected to accept SOA [RFC1033], AXFR
[RFC1034], and IXFR [RFC1995] queries from its configured slave DNS [RFC1034], and IXFR [RFC1995] queries from its configured secondary
servers. The Hidden Master Server SHOULD send NOTIFY messages DNS servers. 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, DNS Homenet Zones are likely to be small, CPE MUST
implement AXFR and SHOULD implement IXFR. implement AXFR and SHOULD implement IXFR.
Hidden Master 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 Master 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 Master Server is to - Limited exchanges: the purpose of the Hidden Primary Server is to
synchronizes with the Public Authoritative Name Server Set, not synchronizes with the Public Authoritative Name Server Set, not
to serve zone. As a result, exchanges are performed with to serve zone. As a result, exchanges are performed with
specific nodes (the Public Authoritative Servers). Then specific nodes (the Public Authoritative Name Server Sets).
exchange types are limited. The only legitimate exchanges are: Then exchange types are limited. The only legitimate exchanges
NOTIFY initiated by the Hidden Master and IXFR or AXFR are: NOTIFY initiated by the Hidden Primary and IXFR or AXFR
exchanges initiated by the Public Authoritative Name Server exchanges initiated by the Public Authoritative Name Server
Set. On the other hand regular authoritative servers would Set. On the other hand regular authoritative servers would
respond any hosts on the home network, and any DNS(SEC) query respond any hosts on the home network, and any DNS(SEC) query
would be considered. The CPE SHOULD filter IXFR/AXFR traffic would be considered. The CPE SHOULD filter IXFR/AXFR traffic
and drop traffic not initiated by the Public Authoritative and drop traffic not initiated by the Public Authoritative Name
Server. The CPE MUST listen for DNS on TCP and UDP and at Server Set. The CPE MUST listen for DNS on TCP and UDP and at
least allow SOA lookups to the DNS Homenet Zone. least allow SOA lookups to the DNS Homenet Zone.
5.2. Securing Synchronization 5.2. Securing Synchronization
Exchange between the Public Servers and the CPE MUST be secured, at Exchange between the Public Authoritative Name Server Sets and the
least for integrity protection and for authentication. This is the CPE MUST be secured, at least for integrity protection and for
case whatever mechanism is used between the CPE and the Public authentication.
Authoritative Name Server Set.
TSIG [RFC2845] or SIG(0) [RFC2931] can be used to secure the DNS TSIG [RFC2845] or SIG(0) [RFC2931] can be used to secure the DNS
communications between the CPE and the Public DNS(SEC) Servers. TSIG communications between the CPE and the Public DNS(SEC) Servers. 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 to roll the keys with SIG(0) is out-of-scope of this
document. The advantage of these mechanisms is that they are only document. The advantage of these mechanisms is that they are only
associated with the DNS application. Not relying on shared libraries associated with the DNS application. Not relying on shared libraries
ease testing and integration. On the other hand, using TSIG, TKEY or ease testing and integration. On the other hand, using TSIG, TKEY or
SIG(0) requires that these mechanisms to be implemented on the SIG(0) requires these mechanisms to be implemented on the DNS(SEC)
DNS(SEC) Server's implementation running on the CPE, which adds Server's implementation running on the CPE, which adds codes.
codes. Another disadvantage is that TKEY does not provides
authentication mechanism. 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] can be used to secure
the transactions between the Public Authoritative Servers and the the transactions between the Public Authoritative Name Server Sets
CPE. The advantage of TLS/DTLS is that this technology is widely and the CPE. The advantage of TLS/DTLS is that this technology is
deployed, and most of the boxes already embeds a TLS/DTLS libraries, widely deployed, and most of the boxes already embeds a TLS/DTLS
eventually taking advantage of hardware acceleration. Then TLS/DTLS libraries, eventually taking advantage of hardware acceleration.
provides authentication facilities and can use certificates to Then TLS/DTLS provides authentication facilities and can use
authenticate the Public Authoritative Server and the CPE. On the certificates to authenticate the Public Authoritative Name Server Set
other hand, using TLS/DTLS requires to integrate DNS exchange over and the CPE. On the other hand, using TLS/DTLS requires to integrate
TLS/DTLS, as well as a new service port. This is why we do not DNS exchange over TLS/DTLS, as well as a new service port. This is
recommend this option. why we do not recommend this option.
IPsec [RFC4301] IKEv2 [RFC7296] can also be used to secure the IPsec [RFC4301] IKEv2 [RFC7296] can also be used to secure the
transactions between the CPE and the Public Authoritative Servers. transactions between the CPE and the Public Authoritative Servers.
Similarly to TLS/DTLS, most CPE already embeds a IPsec stack, and Similarly to TLS/DTLS, most CPE already embeds a IPsec stack, and
IKEv2 provides multiple authentications possibilities with its EAP IKEv2 provides multiple authentications possibilities with its EAP
framework. In addition, IPsec can be used to protect the DNS framework. In addition, IPsec can be used to protect the DNS
exchanges between the CPE and the Public Authoritative Servers exchanges between the CPE and the Public Authoritative Servers
without any modifications of the DNS Servers or client. DNS without any modifications of the DNS Servers or client. DNS
integration over IPsec only requires an additional security policy in integration over IPsec only requires an additional security policy in
the Security Policy Database. One disadvantage of IPsec is that it the Security Policy Database. One disadvantage of IPsec is that it
hardly goes through NATs and firewalls. However, in our case, the hardly goes through NATs and firewalls. However, in our case, the
CPE is connected to the Internet, and IPsec communication between the CPE is connected to the Internet, and IPsec communication between the
CPE and Public Authoritative Server SHOULD NOT be impacted by middle CPE and Public Authoritative Name Server Set SHOULD NOT be impacted
boxes. by middle boxes.
As mentioned above, TSIG, IPsec and TLS/DTLS may be used to secure
transactions between the CPE and the Public Authentication Servers.
The CPE and Public Authoritative Server SHOULD implement TSIG and
IPsec.
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. This
adds complexity to the configuration especially on the CPE side. For adds complexity to the configuration especially on the CPE side. For
this reason, we recommend that CPE MAY use PSK or certificate base this reason, we recommend that CPE MAY use PSK or certificate base
authentication and that Public Authentication Servers MUST support authentication and that Public Authoritative Servers Servers MUST
PSK and certificate based authentication. support PSK and certificate based authentication.
Note also that authentication of the messages exchanged between the
CPE and the Public Authoritative Name Server Set should not involve
the IP address to index the appropriated keys. As detailed in
Section 9, the IP addresses of the Public Authoritative Name Server
Set and the Hidden Primary are subject to change, for example while
the network is being renumbered. This means that the necessary keys
to authenticate transaction must not be indexed using the IP and be
resilient to IP updates.
5.3. CPE Security Policies 5.3. CPE Security Policies
This section details security policies related to the Hidden Master / This section details security policies related to the Hidden Primary
Slave synchronization. / Secondary synchronization.
The Hidden Master, 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 can be performed with port
binding and/or firewall rules. binding and/or firewall rules.
The Hidden Master SHOULD drop on the WAN interface any DNS queries The Hidden Primary SHOULD drop on the WAN interface any DNS queries
that is not issued from the Public Authoritative Server Name Server that is not issued from the Public Authoritative Name Server Set.
Set.
The Hidden Master 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 Master 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 Master 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. This depends 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 the
both the authoritative server and the resolver. The resolver side is both the authoritative server and the resolver. The resolver side is
out of scope of this document, and only the authoritative part is out of scope of this document, and only the authoritative part is
considered. 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 by
the CPE or by the Public Authoritative Servers. Section 6.1 details the CPE or by the Public Authoritative Name Server Sets. Section 6.1
the implications of these two alternatives. Similarly, the secure details the implications of these two alternatives. Similarly, the
delegation can be performed by the CPE or by the Public Authoritative secure delegation can be performed by the CPE or by the Public
Servers. Section 6.2 discusses these two alternatives. Authoritative Servers. 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 Servers. It is performed by the CPE or by the Public Authoritative Name Servers Set.
recommended to sign the zone by the CPE unless there is a strong It is recommended 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 it, like a CPE that is not able to sign the zone.
In that case zone signing may be performed by the Public In that case zone signing may be performed by the Public
Authoritative Servers on behalf of the CPE. Authoritative Name Servers Set 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 Zone equals to securely
optimize DNS resolution. As the Public Zone is signed with optimize DNS resolution. As the Public Zone is signed with
DNSSEC, RRsets are authenticated and thus DNS responses can be DNSSEC, RRsets are authenticated and thus DNS responses can be
validated even though they are not provided by the 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 Master. This respond on behalf of the Public Authoritative Primary. This
could be useful for example if, in the future, the CPE could could be useful for example if, in the future, the CPE could
announce to the home network that the CPE can act a a local announce to the home network that the CPE can act a a local
authoritative master 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 Zone.
On the other hand most CPE host a resolving function, and could On the other hand most CPEs host a resolving function, and
be configured to perform a local lookup to the Homenet Zone could be configured to perform a local lookup to the Homenet
instead of initiating a DNS exchange with the Public Zone instead of initiating a DNS exchange with the Public
Authoritative Master. Note that outsourcing the zone signing Authoritative Primary. Note that outsourcing the zone signing
operation requires that all DNSSEC queries be cached to perform operation requires that all DNSSEC queries be cached to perform
a local lookup, otherwise a resolution with the Public a local lookup, otherwise a resolution with the Public
Authoritative Master is performed. Authoritative Primary is performed.
- 2: Keeping the Homenet Zone and the Public Zone equals to securely - 2: Keeping the Homenet Zone and the Public Zone equals to securely
address the connectivity disruption independence exposed in address the connectivity disruption independence exposed in
[RFC7368] section 4.4.1 and 3.7.5. As local lookup is [RFC7368] section 4.4.1 and 3.7.5. As local lookups are
possible, in case of network disruption, communications within possible in case of network disruption, communications within
the home network can still rely on the DNSSEC service. Note the home network can still rely on the DNSSEC service. Note
that outsourcing the zone signing operation does not address that outsourcing the zone signing operation does not address
connectivity disruption independence with DNSSEC. Instead a connectivity disruption independence with DNSSEC. Instead
fall back to DNS resolution occurs as the local Homenet Zone is local lookup would provide DNS as opposed to DNSSEC responses
not signed. provided by the Public Authoritative Primaries.
- 3: Keeping the Homenet Zone and the Public Zone equals to - 3: Keeping the Homenet Zone and the Public Zone equals to
guarantee coherence between DNS(SEC) responses. Using a unique guarantee coherence between DNS(SEC) responses. Using a unique
zone is one way to guarantee uniqueness of the responses among zone 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 DNS Zone are better guaranteed.
When the Zone is signed by the CPE, it makes modification of When the Zone is signed by the CPE, it makes modification of
the DNS data -- for example for flow redirection -- not the DNS data -- for example for flow redirection -- not
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information at one place may also balance that risk. information at one place may also balance that risk.
6.2. Secure Delegation 6.2. Secure Delegation
The secure delegation is set if the DS RRset is properly set in the The secure delegation is set if the DS RRset is properly set in the
parent zone. Secure delegation can be performed by the CPE or the parent zone. Secure delegation can be performed by the CPE or the
Public Authoritative Servers. Public Authoritative Servers.
The DS RRset can be updated manually by the CPE or the Public The DS RRset can be updated manually by the CPE or the Public
Authoritative Servers. This can be used then with nsupdate for Authoritative Servers. This can be used then with nsupdate for
example bu requires the CPE or the Public Authoritative Server to be example but requires the CPE or the Public Authoritative Server to be
authenticated by the Parent Zone Server. Such a trust channel authenticated by the Parent Zone Server. Such a trust channel
between the CPE and the Parent Zone server may be hard to maintain, between the CPE and the Parent Zone server may be hard to maintain,
and thus may be easier to establish with the Public Authoritative and thus may be easier to establish with the Public Authoritative
Server. On the other hand, [RFC7344] may mitigate such issues. Server. On the other hand, [RFC7344] may mitigate such issues.
7. Handling Different Views 7. Handling Different Views
The DNS Homenet Zone provides information about the home network and The DNS Homenet Zone provides information about the home network and
some user may be tempted to have different information regarding the some user may be tempted to have different information regarding 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 wild Internet.
Each view can be associated to a dedicated Homenet Zone. Note that Each view can be associated to a dedicated Homenet Zone. Note that
this document does not specify how DNS queries coming from the home this document does not specify how DNS queries coming from the home
network are addressed to the DNS(SEC) Homenet Zone. This could be network are addressed to the DNS(SEC) Homenet Zone. This could be
done via the DNS resolver hosted on the CPE for example. done via the DNS resolver hosted on the CPE for example.
This section is not normative. Section 7.1 expose different reasons This section is not normative. Section 7.1 details why some nodes
that result in different views, Section 7.2 briefly describes the may only be reachable from the home network and not from the global
consequences of having distinct views, and Section 7.3 provides Internet. Section 7.2 briefly describes the consequences of having
guidance to avoid this situation. distinct views such as a "home network view" and a "Internet view".
Finally, Section 7.3 provides guidance to on how to resolve names
that are only significant in the home network without creating
different views.
7.1. Motivations 7.1. Misleading Reasons for Local Scope DNS Zone
The main motivation to handle different views is to provide different The main motivation to handle different views is to provide different
information depending on the location the DNS query is emitted. Here information depending on the location the DNS query is emitted. Here
are a few motivations for doing so: are a few motivations for doing so:
- 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 administrate your CPE may not be published
on the Internet. Similarly services like the mapper that on the Internet. Similarly services like the mapper that
registers the devices of your home network may not be published registers the devices of your home network may not be published
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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 Internet.
- 3: If the CPE does not sign the Homenet Zone and outsource the - 3: If the CPE does not sign the Homenet Zone and outsource the
signing process, the two views are at least different since, signing process, the two views are at least different since,
one is protected with DNSSEC whereas the other is not. 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 you are some services will not be Basically, depending on where resolution is performed, some services
available. This may be especially inconvenient with devices with will not be available. This may be especially inconvenient with
multiple interfaces that are attached both to the Internet via a devices with multiple interfaces that are attached both to the
3G/4G interface and to the home network via a WLAN interface. Internet via a 3G/4G interface and to the home network via a WLAN
interface.
Regarding local-scope IP addresses, such device may end up with poor Regarding local-scope IP addresses, such device may end up with poor
connectivity. Suppose, for example, the DNS resolution is performed connectivity. Suppose, for example, the DNS resolution is performed
via the WLAN interface attached to the CPE, the response provides via the WLAN interface attached to the CPE, the response provides
local-scope IP addresses and the communication is initiated on the local-scope IP addresses and 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.
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7.3. Guidance and Recommendations 7.3. Guidance and Recommendations
As exposed in Section 7.2, it is recommended to avoid different As exposed in Section 7.2, it is recommended to avoid different
views. If network administrators chose to implement multiple views, views. If network administrators chose 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 A consequence the DNS(SEC) Homenet Zone is expected to be the exact
copy of the DNS(SEC) Public Zone. As a result, services that are not copy of the DNS(SEC) Public Zone. As a result, services that are not
expected to be published on the Internet should not be part of the expected to be published on the Internet should not be part of the
DNS(SEC) Homenet Zone, local-scope address should not be part of the DNS(SEC) Homenet Zone, local-scope address should not be part of the
DNS(SE) Homenet Zone, and when possible, the CPE should sign the DNS(SEC) Homenet Zone, and when possible, the CPE should sign the
DNSSEC Homenet Zone. DNS(SEC) Homenet Zone.
The DNS(SEC) Homenet Zone is expected to host public information. It The DNS(SEC) Homenet Zone is expected to host public information. It
is not to the DNS service to define local home networks boundaries. is not to the DNS service to define local home networks boundaries.
Instead, local scope information is expected to be provided to the Instead, local scope information is expected to be provided to the
home network using local scope naming services. mDNS [RFC6762] DNS-SD home network using local scope naming services. mDNS [RFC6762] DNS-SD
[RFC6763] are one of these services. Currently mDNS is limited to a [RFC6763] are one of these services. Currently mDNS is limited to a
single link network. However, future protocols are expected to single link network. However, future protocols are expected to
leverage this constraint as pointed out in leverage this constraint as pointed out in
[I-D.ietf-dnssd-requirements]. [I-D.ietf-dnssd-requirements].
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transparently to the end user. transparently to the end user.
[I-D.ietf-homenet-naming-architecture-dhc-options] describes how [I-D.ietf-homenet-naming-architecture-dhc-options] describes how
automatic configuration may be performed. 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 address is so large, that reverse
zone may be confronted to a scalability issue. How to reverse zone zone may be confronted to a scalability issue. How to 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 the
scalability issue. scalability issue.
9. Privacy Considerations 9. Renumbering
This section details how renumbering is handled by the Hidden Primary
server or the Public Authoritative Name Server Set which acts as a
secondary server. Both types of renumbering also designated as
"make-before-break" or "break-before-make" are discussed.
In the make-before-break renumbering scenario, the new prefix is
advertised, the network is configured to prepare the transition to
the new prefix. During a period of time, the two prefixes old and
new coexist, before the old prefix is completely removed. In the
break-before-make renumbering scenario, the new prefix is advertised
making the old prefix obsolete.
Renumbering has been extensively described in [RFC4192] and analyzed
in [RFC7010] and the reader is expected to become familiar with them.
9.1. Hidden Primary
In a renumbering scenario, the Hidden Primary is informed it is being
renumbered. In most cases, it occurs as the whole home network is
being renumbered. As a result, the DNS(SEC) Homenet Zone will also
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
IP addresses be mentioned.
To avoid reachability disruption, IP connectivity information
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
DNS, when it is not reachable anymore. Let for example TTL be the
TTL associate to a RRset of the Homenet Zone, it may be cache during
TTL seconds. Let T_NEW be the time the new IP address replaces the
old IP address in the DNS, and T_OLD_UNREACHABLE the time the old IP
is not reachable anymore. In the case of the make-before-break,
seamless reachability is provided as long as T_OLD_UNREACHABLE -
T_NEW > 2 * TTL. If this is not satisfied, then devices associated
to the old IP address in the home network may become unreachable for
2 * TTL - (T_OLD_UNREACHABLE - T_NEW). In the case of a break-
before-make, T_OLD_UNREACHABLE = T_NEW, and the device may become non
reachable up to 2 * TTL.
Once the DNS(SEC) Homenet Zone file has been updated on the Hidden
Primary, the Hidden Primary needs to inform the Public Authoritative
Naming Server Set that the DNS(SEC) Homenet Zone has been updated and
that the IP address to use to retrieve the updated zone has also been
updated. Both information are updated using the regular DNS
exchanges. More specifically, mechanisms to update a IP address
provided by lower layers with for protocols like SCTP [RFC4960],
MOBIKE [RFC4555] are not considered in this document.
The Hidden Primary informs the Public Authoritative Name Server Set
the DNS(SEC) Homenet Zone has been updated by sending a NOTIFY
payload with the new IP address. In addition, this NOTIFY payload is
authenticated using SIG(0) or TSIG. When the Public Authoritative
Name Server Set receives the NOTIFY payload, it MUST authenticate it.
Note that the cryptographic key used for the authentication should be
indexed by the Homenet Domain Name contained in the NOTIFY payload as
well as the RRSIG. In other words, the IP address should not be used
as an index. If authentication succeeds, the Public Authoritative
Name Server Set MUST also notice the IP address has been modified and
perform a reachability check before updating its primary
configuration. The routability check is performed by sending a SOA
request to the Hidden Primary using the source IP address of the
NOTIFY. This exchange is also secured, and if an authenticated
response is received from the Hidden Primary with the new IP address,
the Public Authoritative Name Server Set updates its configuration
file and retrieve the DNS(SEC) Homenet Zone using an AXFR or a IXFR
exchange.
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
Primary were publicly announced in the DNS, then the IP address
update could have been performed using the DNS as described in
Section 9.2.
9.2. Public Authoritative Name Server Set
Renumbering of the Public Authoritative Name Server Set results in
the Public Authoritative Name Server Set to change its IP address.
The Public Authoritative Name Server Set is a secondary, so its
renumbering does not impact the DNS(SEC) Homenet Zone. In fact,
exchanges to the Public Authoritative Name Server Set are restricted
to the DNS(SEC) Homenet Zone synchronization. In our case, the
Hidden Primary MUST be able to send NOTIFY payloads to the Public
Authoritative Name Server Set.
If the Public Authoritative Name Server Set is configured in Hidden
Primary configuration file with a FQDN, then the update of the IP
address is performed by the DNS(SEC). More specifically, before
sending the NOTIFY, the Hidden Primary performs a DNS(SEC) resolution
to retrieve the IP address of the secondary.
As described in Section 9.1, the Public Authoritative Name Server Set
DNS information should be coherent with the IP plane. Let TTL be the
TTL associated to the Public Authoritative Name Server Set FQDN,
T_NEW the time the new IP address replaces the old one and
T_OLD_UNREACHABLE the time the Public Authoritative Name Server Set
is not reachable anymore with its old IP address. Seamless
reachability is provided as long as T_OLD_UNREACHABLE - T_NEW > 2 *
TTL. If this condition is not met, the Public Authoritative Name
Server Set may be unreachable during 2 * TTL - (T_OLD_UNREACHABLE -
T_NEW). In the case of a break-before-make, T_OLD_UNREACHABLE =
T_NEW, and it may become non reachable up to 2 * TTL.
Some DNS infrastructure uses the IP address to designate the
secondary, in which case, other mechanisms must be found. The reason
for using IP addresses instead of names is generally, to reach an
internal interface that is not designated by a FQDN. Such scenarios
are considered as out of scope in the case of home networks.
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 a few privacy related concerns. entity comes with a few privacy related concerns.
First the DNS Homenet Zone contains a full description of the First the DNS Homenet Zone contains a full description of the
services hosted in the network. These services may not be expected services hosted in the network. These services may not be expected
to be publicly shared although their names remains accessible though to be publicly shared although their names remains accessible though
the Internet. Even though DNS makes information public, the DNS does the Internet. Even though DNS makes information public, the DNS does
not expect to make the complete list of service public. In fact, not expect to make the complete list of service public. In fact,
making information public still requires the key (or FQDN) of each making information public still requires the key (or FQDN) of each
service to be known by the resolver in order to retrieve information service to be known by the resolver in order to retrieve information
of the services. More specifically, making mywebsite.example.com of the services. More specifically, making mywebsite.example.com
public in the DNS, is not sufficient to make resolvers aware of the public in the DNS, is not sufficient to make resolvers aware of the
existence web site. existence web site.
In order to prevent the complete DN(SEC) Homenet Zone to be published In order to prevent the complete DN(SEC) Homenet Zone to be published
on the Internet, one should prevent AXFR queries on the Public on the Internet, one should prevent AXFR queries on the Public
Authoritative Masters. Similarly, to avoid zone-walking one should Authoritative Primaries. Similarly, to avoid zone-walking one should
prefer NSEC3 [RFC5155] over NSEC [RFC4034]. prefer NSEC3 [RFC5155] over NSEC [RFC4034].
When the DNS Homenet Zone is outsourced the end user must be aware When the DNS Homenet Zone is outsourced the end user must 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 eventually the device, by as the DNS
Homenet Zone contains the IP addresses associated to the service, Homenet Zone contains the IP addresses associated to the service,
they limit the scope of the scan. they limit the scope of the scan.
In addition to the DNS Homenet Zone, the third party can also monitor In addition to the DNS Homenet Zone, the third party can also monitor
the traffic associated to the DNS Homenet Zone. This traffic may the traffic associated to the DNS Homenet Zone. This traffic may
provide indication of the services you use, how and when you use provide indication of the services you use, how and when you use
these services. Although, cache may alter this information inside these services. Although, cache may alter this information inside
the home network, it is likely that outside your home network this the home network, it is likely that outside your home network this
information will not be cached. information will not be cached.
10. 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.
10.1. 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 his services and
devices from his home network reachable on the Internet with Names devices from his home network reachable on the Internet with Names
rather than IP addresses. This exposes the home network to attackers rather than IP addresses. This exposes the home network to attackers
since names are expected to provide less randomness than IP since names are expected to provide less randomness than IP
addresses. The naming delegation protects the End User's privacy by addresses. The naming delegation protects the End User's privacy by
not providing the complete zone of the home network to the ISP. not providing the complete zone of the home network to the ISP.
However, using the DNS with names for the home network exposes the However, using the DNS with names for the home network exposes the
home network and its components to dictionary attacks. In fact, with home network and its components to dictionary attacks. In fact, with
IP addresses, the Interface Identifier is 64 bit length leading to IP addresses, the Interface Identifier is 64 bit length leading to
2^64 possibilities for a given subnetwork. This is not to mention 2^64 possibilities for a given subnetwork. This is not to mention
that the subnet prefix is also of 64 bit length, thus providing that the subnet prefix is also of 64 bit length, thus providing
another 2^64 possibilities. On the other hand, names used either for another 2^64 possibilities. On the other hand, names used either for
the home network domain or for the devices present less randomness the home network domain or for the devices present less randomness
(livebox, router, printer, nicolas, jennifer, ...) and thus exposes (livebox, router, printer, nicolas, jennifer, ...) and thus exposes
the devices to dictionary attacks. the devices to dictionary attacks.
10.2. 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 the same
Prefix over time. As a result observing IP addresses provides some Prefix over time. As a result observing IP addresses provides some
ephemeral information about who is accessing the service. On the ephemeral information about who is accessing the service. On the
other hand, Names are not expected to be as volatile as IP addresses. other hand, Names are not expected to be as volatile as IP addresses.
As a result, logging Names, over time, may be more valuable that As a result, logging Names, over time, may be more valuable that
logging IP addresses, especially to profile End User's logging IP addresses, especially to profile End User's
characteristics. 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 we recommend that End Users may choose to respond or not
to PTR DNS queries and may return a NXDOMAIN response. to PTR DNS queries and may return a NXDOMAIN response.
11. IANA Considerations 11.3. DNS Reflection Attacks
An attacker uses a reflection attack when it sends traffic to an
intermediary node that in turn sends back some traffic to the victim.
Motivations for using an intermediary node might be anonymity of the
attacker as wells as amplification of the traffic. Typically, when
the intermediary node is a DNSSEC server, the attacker sends a DNSSEC
query and the victim is likely to receive a DNSSEC response. This
section analyzes how the different components may be involved in a
reflection attack. Section 11.3.1 considers the Hidden Primary,
Section 11.3.2 the Public Authoritative Name Server Set, and
Section 11.3.3 the Public Authoritative Primary.
11.3.1. Reflection Attack involving the Hidden Primary
With the current architecture, the Hidden Primary is only expected to
receive DNS queries of type SOA, AXFR or IXFR. This section analyzes
how these DNS queries may be used by an attacker to perform a
reflection attack.
At first, DNS queries of type AXFR and IXFR uses TCP and as such a
less subject to reflection attacks. This makes SOA query the only
remaining vector of attacks for reflection based on UDP.
Firstly, SOA queries are not associated with a large amplification
factor compared to queries of type "ANY" or to query of non existing
FQDNs. This reduces the probability a DNS query of type SOA is
involved in a DDoS attack. In addition, SOA queries are expected to
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
of SOA requests. Motivations for such flood might be a reflection
attack, but could be also an attack performed against the Hidden
Primary for resource exhaustion. At first, the Hidden Primary only
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
limited to forged packets with the IP address of the secondary
server. In other words, the only victims are the Hidden Primary
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
secondary, and to limit the resource needed to carry on the traffic
by the CPE hosting the Hidden Primary. On the other hand, mitigation
should be appropriately done, as to limit the impact on the
legitimate SOA sent by the secondary.
The main reason for the Public Authoritative Name Server Set to send
a SOA query is to update the SOA RRset after the TTL expires, to
check serial number upon the receipt of a NOTIFY query from the
Hidden Primary or to re-send the SOA request when the response has
not been received. When a flood of SOA queries is received by the
Hidden Primary, the Hidden Primary can assume it is involved in an
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
preserve the CPE resource. 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.
11.3.2. Reflection Attacks involving the Public Authoritative Name
Server Set
The Public Authoritative Name Server Set acts as a secondary toward
the Hidden Primary. The secondary expects to receive NOTIFY query,
SOA responses, AXFR and IXFR responses from the Hidden Primary.
Sending NOTIFY query to the secondary generates a NOTIFY response as
well as an SOA query to the Hidden Primary. As mentioned in
[RFC1996], this is a "known benign denial of service attack". As a
result, the Public Authoritative Name Server Set should enforce rate
limiting on the SOA queries and NOTIFY responses that are sent to the
Hidden Primary. Most likely, when the secondary is flooded with
valid and signed NOTIFY queries it is under a replay attack which is
discussed in Section 11.5. The key thing here is that the secondary
is likely to be designed to address much traffic than the Hidden
Primary hosted on a CPE.
This paragraph details how the secondary may limit the NOTIFY
queries. Because the Hidden Primary may be renumbered, the secondary
may not proceed to IP filtering based on the IP address. In
addition, a given secondary may be shared among multiple Hidden
Primaries which makes filtering rules based on IP harder to set. At
last, 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
NOTIFY for a given DNS Homenet Zone is expected to have a very
limited number of different IP addresses even though renumbering
occurs. As a result, the secondary, can rate limit incoming NOTIFY
queries.
It is recommended the Hidden Primary sends NOTIFY as long as the zone
has not been updated by the secondary. Multiple SOA queries may
indicate the secondary is under attack.
11.3.3. Reflection Attacks involving the Public Authoritative Primary
The Public Authoritative Primary implication of reflection attacks is
similar as any public authoritative server. These is not specific to
the architecture described in this document, and thus considered as
out of scope.
In fact, one of the motivation of the architecture described in this
document was to expose the Public Authoritative Primary to attacks
instead of the CPE.
11.4. Flooding Attack
The purpose of flooding attacks is mostly resource exhaustion where
the resource can be bandwidth or CPU for example.
One of the goal of the architecture described in the document is to
limit the surface of attack for the CPE. This is done, by
outsourcing the DNS service to the Public Authoritative Primaries.
By doing so, the CPE limits its DNS interactions between the Hidden
Primary and the Public Authoritative Name Server Set. This limits the
number of entity the CPE interacts with as well as the scope of DNS
exchanges - basically NOTIFY, SOA, AXFR, IXFR.
The use of an authenticated channel with SIG(0) or TSIG between the
CPE and the Public Authoritative Name Server Set, enables to detect
illegitimate DNS queries, and take appropriated actions - like
dropping the queries. If signatures are validated, then most likely,
the CPE is under a replay attack, as detailed in Section 11.5
In order to limit the resource required for authentication, it is
recommended to use TSIG that uses symmetric cryptography over SIG(0)
that uses asymmetric cryptography.
11.5. Replay Attack
Replay attacks consist in sending a message that has already been
sent. As the Hidden Primary and the Public Authoritative Name Server
Set use an authenticated channel, replay attacks are mostly expected
to used over forged DNS queries in order to provide valid traffic.
On an attacker points of view, using a correctly authenticated DNS
query, may not be detected as an attack, and thus may generate the
corresponding response. Generating and sending a response consumes
more resources then dropping the query and thus could be used for
resource exhaustion attacks. In addition, as the authentication is
performed at the DNS layer, the IP address could be impersonated in
order to perform a reflection attack.
Section 11.3 details how to mitigate reflection attacks and
Section 11.4 details how to mitigate resource exhaustion. Both
section assumes a context of DoS with a flood of DNS queries. This
section address replay attack as a way to limit the surface of these
attacks.
As SIG(0) and TSIG uses inception and expiration time, the time frame
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
loose time synchronization of the devices and short live time for the
message. As a result, better time synchronization policies could
reduce the time window of the attack.
12. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
12. 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 and Michael Richardson, Ray Bellis for their feed backs on Abrahamson, Michael Richardson and Ray Bellis for their feed backs 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. outsourcing the zone signing operation outside the CPE; Ray Hunter,
Mark Andrew and Peter Koch for clarifying the renumbering.
13. References 14. References
13.1. 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.
[RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995,
August 1996. August 1996.
skipping to change at page 21, line 22 skipping to change at page 28, line 28
[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
(MOBIKE)", RFC 4555, June 2006.
[RFC4960] Stewart, R., "Stream Control Transmission Protocol", RFC
4960, September 2007.
[RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS [RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
Security (DNSSEC) Hashed Authenticated Denial of Security (DNSSEC) Hashed Authenticated Denial of
Existence", RFC 5155, March 2008. Existence", RFC 5155, March 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008. (TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5936] Lewis, E. and A. Hoenes, "DNS Zone Transfer Protocol [RFC5936] Lewis, E. and A. Hoenes, "DNS Zone Transfer Protocol
(AXFR)", RFC 5936, June 2010. (AXFR)", RFC 5936, June 2010.
skipping to change at page 21, line 48 skipping to change at page 29, line 12
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
February 2013. February 2013.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, February 2013. Discovery", RFC 6763, February 2013.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2 Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, October 2014. (IKEv2)", STD 79, RFC 7296, October 2014.
13.2. Informational References 14.2. Informational References
[I-D.howard-dnsop-ip6rdns] [I-D.howard-dnsop-ip6rdns]
Howard, L., "Reverse DNS in IPv6 for Internet Service Howard, L., "Reverse DNS in IPv6 for Internet Service
Providers", draft-howard-dnsop-ip6rdns-00 (work in Providers", draft-howard-dnsop-ip6rdns-00 (work in
progress), June 2014. progress), June 2014.
[I-D.ietf-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-04 (work in progress), October ietf-dnssd-requirements-06 (work in progress), March 2015.
2014.
[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-00 (work in ietf-homenet-naming-architecture-dhc-options-01 (work in
progress), September 2014. progress), February 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
Renumbering an IPv6 Network without a Flag Day", RFC 4192,
September 2005.
[RFC7010] Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W.
George, "IPv6 Site Renumbering Gap Analysis", RFC 7010,
September 2013.
[RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating [RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating
DNSSEC Delegation Trust Maintenance", RFC 7344, September DNSSEC Delegation Trust Maintenance", RFC 7344, September
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]
-06:
Ray Hunter is added in acknowledgment.
Adding Renumbering section with comments from Dallas meeting
Replacing Master / Primary - Slave / Secondary
Security Consideration has been updated with Reflection 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 Masters (and without necessarily requesting the Public Primaries (and
eventually the Hidden Master) 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
Documenting how to handle reverse zones Documenting how to handle reverse zones
Adding reference to RFC 2308 Adding reference to RFC 2308
-04: -04:
*Clarifications on zone signing *Clarifications on zone signing
*Rewording *Rewording
skipping to change at page 23, line 35 skipping to change at page 31, line 20
*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 Master(s)". "Public Authoritative replaced by "Public Authoritative Primary(ies)". "Public
Server Management Interface" is replaced by "Public Authoritative Authoritative Server Management Interface" is replaced by "Public
Name Server Set". Authoritative Name Server Set".
-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 24, line 27 skipping to change at page 32, line 12
* I remove the terminology and expose it in the figures A and B. * I remove the terminology and expose it in the figures A and B.
* remove the Front End Homenet Naming Architecture to Homenet Naming * remove the Front End Homenet Naming Architecture to Homenet Naming
-01: -01:
* Added C. Griffiths as co-author. * Added C. Griffiths as co-author.
* Updated section 5.4 and other sections of draft to update section * Updated section 5.4 and other sections of draft to update section
on Hidden Master / Slave functions with CPE as Hidden Master/Homenet on Hidden Primary / Slave functions with CPE as Hidden Primary/
Server. Homenet Server.
* 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 Master. 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
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