draft-ietf-dhc-dhcpv6-privacy-05.txt   rfc7824.txt 
dhc S. Krishnan Internet Engineering Task Force (IETF) S. Krishnan
Internet-Draft Ericsson Request for Comments: 7824 Ericsson
Intended status: Informational T. Mrugalski Category: Informational T. Mrugalski
Expires: August 27, 2016 ISC ISSN: 2070-1721 ISC
S. Jiang S. Jiang
Huawei Technologies Co., Ltd Huawei Technologies Co., Ltd.
February 24, 2016 May 2016
Privacy considerations for DHCPv6 Privacy Considerations for DHCPv6
draft-ietf-dhc-dhcpv6-privacy-05
Abstract Abstract
DHCPv6 is a protocol that is used to provide addressing and DHCPv6 is a protocol that is used to provide addressing and
configuration information to IPv6 hosts. This document describes the configuration information to IPv6 hosts. This document describes the
privacy issues associated with the use of DHCPv6 by the Internet privacy issues associated with the use of DHCPv6 by Internet users.
users. It is intended to be an analysis of the present situation and It is intended to be an analysis of the present situation and does
does not propose any solutions. not propose any solutions.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for informational purposes.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
This Internet-Draft will expire on August 27, 2016. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7824.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction ....................................................4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology .....................................................4
3. Identifiers in DHCPv6 options and fields . . . . . . . . . . 3 3. Identifiers in DHCPv6 Options and Fields ........................5
3.1. Source IPv6 address . . . . . . . . . . . . . . . . . . . 4 3.1. Source IPv6 Address ........................................5
3.2. DUID . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. DUID .......................................................5
3.3. Client Identifier Option . . . . . . . . . . . . . . . . 5 3.3. Client Identifier Option ...................................6
3.4. IA_NA, IA_TA, IA_PD, IA Address and IA Prefix Options . . 5 3.4. IA_NA, IA_TA, IA_PD, IA Address, and IA Prefix Options .....6
3.5. Client FQDN Option . . . . . . . . . . . . . . . . . . . 5 3.5. Client FQDN Option .........................................6
3.6. Client Link-layer Address Option . . . . . . . . . . . . 6 3.6. Client Link-Layer Address Option ...........................7
3.7. Option Request Option . . . . . . . . . . . . . . . . . . 6 3.7. Option Request Option ......................................7
3.8. Vendor Class and Vendor-specific Information Options . . 6 3.8. Vendor Class and Vendor-Specific Information Options .......7
3.9. Civic Location Option . . . . . . . . . . . . . . . . . . 7 3.9. Civic Location Option ......................................8
3.10. Coordinate-Based Location Option . . . . . . . . . . . . 7 3.10. Coordinate-Based Location Option ..........................8
3.11. Client System Architecture Type Option . . . . . . . . . 7 3.11. Client System Architecture Type Option ....................8
3.12. Relay Agent Options . . . . . . . . . . . . . . . . . . . 7 3.12. Relay Agent Options .......................................8
3.12.1. Subscriber ID Option . . . . . . . . . . . . . . . . 7 3.12.1. Subscriber-ID Option ...............................9
3.12.2. Interface ID Option . . . . . . . . . . . . . . . . 8 3.12.2. Interface ID Option ................................9
3.12.3. Remote ID Option . . . . . . . . . . . . . . . . . . 8 3.12.3. Remote ID Option ...................................9
3.12.4. Relay-ID Option . . . . . . . . . . . . . . . . . . 8 3.12.4. Relay-ID Option ....................................9
4. Existing Mechanisms That Affect Privacy . . . . . . . . . . . 8 4. Existing Mechanisms That Affect Privacy ........................10
4.1. Temporary addresses . . . . . . . . . . . . . . . . . . . 9 4.1. Temporary Addresses .......................................10
4.2. DNS Updates . . . . . . . . . . . . . . . . . . . . . . . 9 4.2. DNS Updates ...............................................10
4.3. Allocation strategies . . . . . . . . . . . . . . . . . . 9 4.3. Allocation Strategies .....................................10
5. Attacks . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5. Attacks ........................................................12
5.1. Device type discovery (fingerprinting) . . . . . . . . . 11 5.1. Device Type Discovery (Fingerprinting) ....................12
5.2. Operating system discovery (fingerprinting) . . . . . . . 11 5.2. Operating System Discovery (Fingerprinting) ...............12
5.3. Finding location information . . . . . . . . . . . . . . 11 5.3. Finding Location Information ..............................12
5.4. Finding previously visited networks . . . . . . . . . . . 12 5.4. Finding Previously Visited Networks .......................13
5.5. Finding a stable identity . . . . . . . . . . . . . . . . 12 5.5. Finding a Stable Identity .................................13
5.6. Pervasive monitoring . . . . . . . . . . . . . . . . . . 12 5.6. Pervasive Monitoring ......................................13
5.7. Finding client's IP address or hostname . . . . . . . . . 13 5.7. Finding a Client's IP Address or Hostname .................14
5.8. Correlation of activities over time . . . . . . . . . . . 13 5.8. Correlation of Activities over Time .......................14
5.9. Location tracking . . . . . . . . . . . . . . . . . . . . 13 5.9. Location Tracking .........................................14
5.10. Leasequery & bulk leasequery . . . . . . . . . . . . . . 14 5.10. Leasequery and Bulk Leasequery ...........................15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14 6. Security Considerations ........................................15
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 14 7. Privacy Considerations .........................................15
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 8. References .....................................................16
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 8.1. Normative References ......................................16
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 8.2. Informative References ....................................16
10.1. Normative References . . . . . . . . . . . . . . . . . . 15 Acknowledgements ..................................................18
10.2. Informative References . . . . . . . . . . . . . . . . . 15 Authors' Addresses ................................................18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
DHCPv6 [RFC3315] is a protocol that is used to provide addressing and DHCPv6 [RFC3315] is a protocol that is used to provide addressing and
configuration information to IPv6 hosts. DHCPv6 uses several configuration information to IPv6 hosts. DHCPv6 uses several
identifiers that could become a source for gleaning information about identifiers that could become a source for gleaning information about
the IPv6 host. This information may include device type, operating the IPv6 host. This information may include device type, operating
system information, location(s) that the device may have previously system information, location(s) that the device may have previously
visited, etc. This document discusses the various identifiers used visited, etc. This document discusses the various identifiers used
by DHCPv6 and the potential privacy issues [RFC6973]. In particular, by DHCPv6 and the potential privacy issues [RFC6973]. In particular,
it also takes into consideration the problem of pervasive monitoring it also takes into consideration the problem of pervasive monitoring
[RFC7258]. [RFC7258].
Future works may propose protocol changes to fix the privacy issues Future works may propose protocol changes to fix the privacy issues
that have been analyzed in this document. Protocol changes are out that have been analyzed in this document. See [RFC7844] for one of
of scope for this document. such changes. Protocol changes are out of scope for this document.
The primary focus of this document is around privacy considerations The primary focus of this document is around privacy considerations
for clients to support client mobility and connection to random for clients to support client mobility and connection to random
networks. The privacy of DHCPv6 servers and relay agents are networks. The privacy of DHCPv6 servers and relay agents are
considered less important as they are typically open for public considered less important as they are typically open for public
services. And, it is generally assumed that relay agent to server services. And, it is generally assumed that communication from the
communication is protected from casual snooping, as that relay agent to the server is protected from casual snooping, as that
communication occurs in the provider's backbone. Nevertheless, the communication occurs in the provider's backbone. Nevertheless, the
topics involving relay agents and servers are explored to some topics involving relay agents and servers are explored to some
degree. However, future work may want to further explore privacy of degree. However, future work may want to further explore privacy of
DHCPv6 servers and relay agents. DHCPv6 servers and relay agents.
2. Terminology 2. Terminology
Naming convention from [RFC3315] and related is used throughout this Naming conventions from [RFC3315] and other DHCPv6-related RFCs are
document. In addition the following terminology is used: used throughout this document. In addition, the following term is
used:
Stable identifier - Any property disclosed by a DHCPv6 client that Stable identifier: Any property disclosed by a DHCPv6 client that
does not change over time or changes very infrequently and is does not change over time or changes very infrequently and is
unique for said client in a given context. Examples include unique for said client in a given context. Examples include
MAC address, client-id, and a hostname. Some identifiers may Media Access Control (MAC) address, client-id, and a
be considered stable only under certain conditions, for hostname. Some identifiers may be considered stable only
example one client implementation may keep its client-id under certain conditions; for example, one client
stored in stable storage while another may generate it on the implementation may keep its client-id stored in stable
fly and use a different one after each boot. Stable storage whereas another may generate it on the fly and use a
identifiers may or may not be globally unique. different one after each boot. Stable identifiers may or may
not be globally unique.
3. Identifiers in DHCPv6 options and fields 3. Identifiers in DHCPv6 Options and Fields
In DHCPv6, there are many options that include identification In DHCPv6, there are many options that include identification
information or that can be used to extract identification information information or that can be used to extract identification information
about the client. This section enumerates various options or fields about the client. This section enumerates various options or fields
and the identifiers conveyed in them, which can be used to disclose and the identifiers conveyed in them, which can be used to disclose
client identification. The attacks that are enabled by such client identification. The attacks that are enabled by such
disclosures are detailed in Section 5. disclosures are detailed in Section 5.
3.1. Source IPv6 address 3.1. Source IPv6 Address
Although IPv6 link-local address is technically not a part of DHCPv6, Although an IPv6 link-local address is technically not a part of
it appears in the DHCPv6 transmissions, so it is mentioned here for DHCPv6, it appears in the DHCPv6 transmissions, so it is mentioned
completeness. here for completeness.
If the client does not use privacy extensions (see [RFC4941]) or If the client does not use privacy extensions (see [RFC4941]) or
similar solutions and its IPv6 link-local address is based on similar solutions and its IPv6 link-local address is based on a
physical link-layer address, this information is disclosed to the physical link-layer address, this information is disclosed to the
DHCPv6 server and to anyone who manages to intercept this DHCPv6 server and to anyone who manages to intercept this
transmission. transmission.
There are multiple cases where IPv6 link-local addresses are used in There are multiple cases where IPv6 link-local addresses are used in
DHCPv6. Initial client transmissions are always sent from the IPv6 DHCPv6. Initial client transmissions are always sent from the IPv6
link-local addresses even when the server unicast option (see link-local addresses even when the server unicast option (see
Sections 22.12 and 18 of [RFC3315] for details) is enabled. If there Sections 22.12 and 18 of [RFC3315] for details) is enabled. If there
are relay agents, they forward client's traffic wrapped in Relay- are relay agents, they forward the client's traffic wrapped in Relay-
forward and store original source IPv6 address in peer-address field. forward and store original source IPv6 address in peer-address field.
3.2. DUID 3.2. DUID
Each DHCPv6 client and server has a DHCPv6 Unique Identifier (DUID) Each DHCPv6 client and server has a DHCP Unique Identifier (DUID)
[RFC3315]. The DUID is designed to be unique across all DHCPv6 [RFC3315]. The DUID is designed to be unique across all DHCPv6
clients and servers, and to remain stable after it has been initially clients and servers and to remain stable after it has been initially
generated. The DUID can be of different forms. Commonly used forms generated. The DUID can be of different forms. Commonly used forms
are based on the link-layer address of one of the device's network are based on the link-layer address of one of the device's network
interfaces (with or without a timestamp), on the Universally Unique interfaces (with or without a timestamp) [RFC3315], or on the
IDentifier (UUID) [RFC6355]. The default type, defined in Universally Unique IDentifier (UUID) [RFC6355]. The default type,
Section 9.2 of [RFC3315] is DUID-LLT that is based on link-layer defined in Section 9.2 of [RFC3315] is DUID-LLT that is based on
address. It is commonly implemented in most popular clients. link-layer address. It is commonly implemented in most popular
clients.
It is important to understand DUID lifecycle. Clients and servers It is important to understand DUID life cycle. Clients and servers
are expected to generate their DUID once (during first operation) and are expected to generate their DUID once (during first operation) and
store it in a non-volatile storage or use the same deterministic store it in a non-volatile storage or use the same deterministic
algorithm to generate the same DUID value again. This means that algorithm to generate the same DUID value again. This means that
most implementations will use the available link-layer address during most implementations will use the available link-layer address during
its first boot. Even if the administrator enables link-layer address their first boot. Even if the administrator enables link-layer
randomization, it is likely that it was not yet enabled during the address randomization, it is likely that it was not yet enabled
first device boot. Hence the original, unobfuscated link-layer during the first device boot. Hence, the original, unobfuscated
address will likely end up being announced as client DUID, even if link-layer address will likely end up being announced as the client
the link-layer address has changed (or even if being changed on a DUID, even if the link-layer address has changed (or even if being
periodic basis). The exposure of the original link-layer address in changed on a periodic basis). The exposure of the original link-
DUID will also undermine other privacy extensions such as [RFC4941]. layer address in DUID will also undermine other privacy extensions
such as [RFC4941].
3.3. Client Identifier Option 3.3. Client Identifier Option
The Client Identifier Option (OPTION_CLIENTID) [RFC3315] is used to The Client Identifier option (OPTION_CLIENTID) [RFC3315] is used to
carry the DUID of a DHCPv6 client between a client and a server. carry the DUID of a DHCPv6 client between a client and a server.
There is an analogous Server Identifier Option but it is not as There is an analogous Server Identifier Option, but it is not as
interesting in the privacy context (unless a host can be convinced to interesting in the privacy context (unless a host can be convinced to
start acting as a server). See Section 3.2 for relevant discussion start acting as a server). See Section 3.2 for relevant discussion
about DUIDs. about DUIDs.
3.4. IA_NA, IA_TA, IA_PD, IA Address and IA Prefix Options 3.4. IA_NA, IA_TA, IA_PD, IA Address, and IA Prefix Options
The Identity Association for Non-temporary Addresses (IA_NA) option The Identity Association for Non-temporary Addresses (IA_NA) option
[RFC3315] is used to carry the parameters and any non-temporary [RFC3315] is used to carry the parameters and any non-temporary
addresses associated with the given IA_NA. The Identity Association addresses associated with the given IA_NA. The Identity Association
for Temporary Addresses (IA_TA) option [RFC3315] is analogous to the for Temporary Addresses (IA_TA) option [RFC3315] is analogous to the
IA_NA option but for temporary addresses. The IA Address option IA_NA option but is used for temporary addresses. The IA Address
[RFC3315] is used to specify IPv6 addresses associated with an IA_NA option [RFC3315] is used to specify IPv6 addresses associated with an
or an IA_TA and is encapsulated within the Options field of such an IA_NA or an IA_TA and is encapsulated within the Options field of
IA_NA or IA_TA option. The Identity Association for Prefix such an IA_NA or IA_TA option. The Identity Association for Prefix
Delegation (IA_PD) [RFC3633] option is used to carry the prefixes Delegation (IA_PD) [RFC3633] option is used to carry the prefixes
that are assigned to the requesting router. IA Prefix option that are assigned to the requesting router. IA Prefix option
[RFC3633] is used to specify IPv6 prefixes associated with an IA_PD [RFC3633] is used to specify IPv6 prefixes associated with an IA_PD
and is encapsulated within the Options field of such an IA_PD option. and is encapsulated within the Options field of such an IA_PD option.
To differentiate between instances of the same type of IA containers To differentiate between instances of the same type of IA containers
for a client, each IA_NA, IA_TA and IA_PD options have an IAID field for a client, each IA_NA, IA_TA, and IA_PD options have an IAID field
with a unique value for a given IA type. It is up to the client to with a unique value for a given IA type. It is up to the client to
pick unique IAID values. At least one popular implementation uses pick unique IAID values. At least one popular implementation uses
last four octets of the link-layer address. In most cases, that the last four octets of the link-layer address. In most cases, that
means that merely two bytes are missing for a full link-layer address means that merely two bytes are missing for a full link-layer address
reconstruction. However, the first three octets in a typical link- reconstruction. However, the first three octets in a typical link-
layer address are vendor identifier. That can be determined with layer address are vendor identifiers. That can be determined with a
high level of certainty using other means, thus allowing full link- high level of certainty using other means, thus allowing full link-
layer address discovery. layer address discovery.
3.5. Client FQDN Option 3.5. Client FQDN Option
The Client Fully Qualified Domain Name (FQDN) option [RFC4704] is The Client Fully Qualified Domain Name (FQDN) option [RFC4704] is
used by DHCPv6 clients and servers to exchange information about the used by DHCPv6 clients and servers to exchange information about the
client's fully qualified domain name and about who has the client's FQDN and about who has the responsibility for updating the
responsibility for updating the DNS with the associated AAAA and PTR DNS with the associated AAAA and PTR RRs.
RRs.
A client can use this option to convey all or part of its domain name A client can use this option to convey all or part of its domain name
to a DHCPv6 server for the IPv6-address-to-FQDN mapping. In most to a DHCPv6 server for the IPv6-address-to-FQDN mapping. In most
case a client sends its hostname as a hint for the server. The cases, a client sends its hostname as a hint for the server. The
DHCPv6 server may be configured to modify the supplied name or to DHCPv6 server may be configured to modify the supplied name or to
substitute a different name. The server should send its notion of substitute a different name. The server should send its notion of
the complete FQDN for the client in the Domain Name field. the complete FQDN for the client in the Domain Name field.
3.6. Client Link-layer Address Option 3.6. Client Link-Layer Address Option
The Client link-layer address option [RFC6939] is used by first-hop The client link-layer address option [RFC6939] is used by first-hop
DHCPv6 relays to provide the client's link-layer address towards the DHCPv6 relays to provide the client's link-layer address towards the
server. server.
DHCPv6 relay agents that receive messages originating from clients DHCPv6 relay agents that receive messages originating from clients
may include the link-layer source address of the received DHCPv6 may include the link-layer source address of the received DHCPv6
message in the Client Link-Layer Address option, in relayed DHCPv6 message in the client link-layer address option, in relayed DHCPv6
Relay-Forward messages. Relay-forward messages.
3.7. Option Request Option 3.7. Option Request Option
DHCPv6 clients include an Option Request option [RFC3315] in DHCPv6 DHCPv6 clients include an Option Request option [RFC3315] in DHCPv6
messages to inform the server about options the client wants the messages to inform the server about options the client wants the
server to send to the client. server to send to the client.
The content of an Option Request option are the option codes for The contents of an Option Request option are the option codes for
options requested by the client. The client may additionally include options requested by the client. The client may additionally include
instances of those options that are identified in the Option Request instances of those options that are identified in the Option Request
option, with data values as hints to the server about parameter option, with data values as hints to the server about parameter
values the client would like to have returned. values the client would like to have returned.
3.8. Vendor Class and Vendor-specific Information Options 3.8. Vendor Class and Vendor-Specific Information Options
The Vendor Class option, defined in Section 22.16 of [RFC3315], is The Vendor Class option, defined in Section 22.16 of [RFC3315], is
used by a DHCPv6 client to identify the vendor that manufactured the used by a DHCPv6 client to identify the vendor that manufactured the
hardware on which the client is running. hardware on which the client is running.
The Vendor-specific Information option, defined in Section 22.17 of The Vendor-specific information option, defined in Section 22.17 of
[RFC3315], includes enterprise number, which identifies the client's [RFC3315], includes enterprise number, which identifies the client's
vendor and often includes a number of additional parameters that are vendor and often includes a number of additional parameters that are
specific to a given vendor. That may include any type of information specific to a given vendor. That may include any type of information
the vendor deems useful. It should be noted that this information the vendor deems useful. It should be noted that this information
may be present (and different) in both directions: client to server may be present (and different) in both directions: client-to-server
and server to client communications. and server-to-client communications.
The information contained in the data area of this option is The information contained in the data area of this option is
contained in one or more opaque fields that identify details of the contained in one or more opaque fields that identify details of the
hardware configuration, for example, the version of the operating hardware configuration, for example, the version of the operating
system the client is running or the amount of memory installed on the system the client is running or the amount of memory installed on the
client. client.
3.9. Civic Location Option 3.9. Civic Location Option
DHCPv6 servers use the Civic Location option [RFC4776] to deliver DHCPv6 servers use the Civic Location option [RFC4776] to deliver
location information (the civic and postal addresses) from the DHCPv6 location information (the civic and postal addresses) from the DHCPv6
server to DHCPv6 clients. It may refer to three locations: the server to DHCPv6 clients. It may refer to three locations: the
location of the DHCPv6 server, the location of the network element location of the DHCPv6 server, the location of the network element
believed to be closest to the client, or the location of the client, believed to be closest to the client, or the location of the client,
identified by the "what" element within the option. identified by the "what" element within the option.
3.10. Coordinate-Based Location Option 3.10. Coordinate-Based Location Option
The GeoLoc options [RFC6225] are used by DHCPv6 server to provide The GeoLoc options [RFC6225] are used by the DHCPv6 server to provide
coordinate-based geographic location information to DHCPv6 clients. coordinate-based geographic location information to DHCPv6 clients.
They enable a DHCPv6 client to obtain its location. They enable a DHCPv6 client to obtain its location.
3.11. Client System Architecture Type Option 3.11. Client System Architecture Type Option
The Client System Architecture Type option [RFC5970] is used by The Client System Architecture Type option [RFC5970] is used by the
DHCPv6 client to send a list of supported architecture types to the DHCPv6 client to send a list of supported architecture types to the
DHCPv6 server. It is used by clients that must be booted using the DHCPv6 server. It is used by clients that must be booted using the
network rather than from local storage, so the server can decide network rather than from local storage, so the server can decide
which boot file should be provided to the client. which boot file should be provided to the client.
3.12. Relay Agent Options 3.12. Relay Agent Options
A DHCPv6 relay agent may include a number of options. Those option A DHCPv6 relay agent may include a number of options. Those options
contain information that can be used to identify the client. Those contain information that can be used to identify the client. Those
options are almost exclusively exchanged between the relay agent and options are almost exclusively exchanged between the relay agent and
the server, thus never leaving the operators network. In particular, the server, thus never leaving the operators network. In particular,
they're almost never present in the last wireless hop in case of WiFi they're almost never present in the last wireless hop in case of WiFi
networks. The only exception to that rule is somewhat infrequently networks. The only exception to that rule is somewhat infrequently
used Relay Supplied Options option [RFC6422]. This fact implies that used Relay-Supplied Options option [RFC6422]. This fact implies that
the threat model related relay options is slightly different. the threat-model-related relay options are slightly different.
Traffic sniffing at the last hop and related class of attacks Traffic sniffing at the last hop and related class of attacks
typically do not apply. On the other hand, all attacks that involve typically do not apply. On the other hand, all attacks that involve
operator's intfrastructure (either willing or coerced cooperation or the operator's infrastructure (either willing or coerced cooperation
infrastructure being compromised) usually apply. or infrastructure being compromised) usually apply.
The following subsections describe various options inserted by the The following subsections describe various options inserted by the
relay agents. relay agents.
3.12.1. Subscriber ID Option 3.12.1. Subscriber-ID Option
A DHCPv6 relay may include a Subscriber ID option [RFC4580] to A DHCPv6 relay may include a Subscriber-ID option [RFC4580] to
associate some provider-specific information with clients' DHCPv6 associate some provider-specific information with clients' DHCPv6
messages that is independent of the physical network configuration. messages that is independent of the physical network configuration.
In many deployments, the relay agent that inserts this option is In many deployments, the relay agent that inserts this option is
configured to use client's link-layer address as Subscriber ID. configured to use client's link-layer address as Subscriber-ID.
3.12.2. Interface ID Option 3.12.2. Interface ID Option
A DHCPv6 relay includes the Interface ID [RFC3315] option to identify A DHCPv6 relay includes the Interface ID option [RFC3315] to identify
the interface on which it received the client message that is being the interface on which it received the client message that is being
relayed. relayed.
Although in principle Interface ID can be arbitrarily long with Although, in principle, the Interface ID can be arbitrarily long with
completely random values, it is sometimes a text string that includes completely random values, it is sometimes a text string that includes
the relay agent name followed by interface name. This can be used the relay agent name followed by the interface name. This can be
for fingerprinting the relay or determining client's point of used for fingerprinting the relay or determining a client's point of
attachment. attachment.
3.12.3. Remote ID Option 3.12.3. Remote ID Option
A DHCPv6 relay includes a Remote ID option [RFC4649] to identify the A DHCPv6 relay includes a Remote ID option [RFC4649] to identify the
remote host end of the circuit. remote host end of the circuit.
The remote-id is vendor specific, for which the vendor is indicated The remote-id is vendor specific, for which the vendor is indicated
in the enterprise-number field. The remote-id field may encode the in the enterprise-number field. The remote-id field may encode the
information that identified DHCPv6 clients: information that identified DHCPv6 clients:
skipping to change at page 8, line 41 skipping to change at page 9, line 47
o a "user name" prompted for by a Remote Access Server o a "user name" prompted for by a Remote Access Server
o a remote caller ATM address o a "modem ID" of a cable data modem o a remote caller ATM address o a "modem ID" of a cable data modem
o the remote IP address of a point-to-point link o the remote IP address of a point-to-point link
o an interface or port identifier o an interface or port identifier
3.12.4. Relay-ID Option 3.12.4. Relay-ID Option
Relay agent may include Relay-ID [RFC5460], which contains a unique Relay agent may include Relay-ID option [RFC5460], which contains a
relay agent identifier. While its intended use is to provide unique relay agent identifier. While its intended use is to provide
additional information for the server, so it would be able to respond additional information for the server, so it would be able to respond
to leasequeries later, this information can be also used to identify to leasequeries later, this information can be also used to identify
client's location within the network. a client's location within the network.
4. Existing Mechanisms That Affect Privacy 4. Existing Mechanisms That Affect Privacy
This section describes deployed DHCPv6 mechanisms that can affect This section describes deployed DHCPv6 mechanisms that can affect
privacy. privacy.
4.1. Temporary addresses 4.1. Temporary Addresses
[RFC3315] defines a mechanism for a client to request temporary [RFC3315] defines a mechanism for a client to request temporary
addresses. The idea behind temporary addresses is that a client can addresses. The idea behind temporary addresses is that a client can
request a temporary address for a specific purpose, use it, and then request a temporary address for a specific purpose, use it, and then
never renew it. i.e. let it expire. never renew it (i.e., let it expire).
There are a number of serious issues, both related to protocol and There are a number of serious issues, both related to protocol and
its implementations, that make temporary addresses nearly useless for its implementations, that make temporary addresses nearly useless for
their original goal. First, [RFC3315] does not include T1 and T2 their original goal. First, [RFC3315] does not include T1 and T2
renewal timers in IA_TA (a container for temporary addresses). renewal timers in IA_TA (a container for temporary addresses).
However, in section 18.1.3 it explicitly mentions that temporary However, in Section 18.1.3, it explicitly mentions that temporary
addresses can be renewed. Client implementations may mistakenly addresses can be renewed. Client implementations may mistakenly
renew temporary addresses if they are not careful (i.e., by including renew temporary addresses if they are not careful (i.e., by including
the IA_TA with the same IAID in Renew or Rebind requests, rather than the IA_TA with the same IAID in Renew or Rebind requests, rather than
a new IAID - see [RFC3315] Section 22.5), thus forfeiting short a new IAID -- see Section 22.5 of [RFC3315]), thus forfeiting short
liveness. [RFC4704] does not explicitly prohibit servers to update liveness. [RFC4704] does not explicitly prohibit servers from
DNS for assigned temporary addresses and there are implementations updating DNS for assigned temporary addresses, and there are
that can be configured to do that. However, this is not advised as implementations that can be configured to do that. However, this is
publishing a client's IPv6 address in DNS that is publicly available not advised as publishing a client's IPv6 address in DNS that is
is a major privacy breach. publicly available is a major privacy breach.
4.2. DNS Updates 4.2. DNS Updates
The Client FQDN Option[RFC4704] used along with DNS Update [RFC2136] The Client FQDN option [RFC4704] used along with DNS UPDATE [RFC2136]
defines a mechanism that allows both clients and server to insert defines a mechanism that allows both clients and the server to insert
into the DNS domain information about clients. Both forward (AAAA) information about clients into the DNS domain. Both forward (AAAA)
and reverse (PTR) resource records can be updated. This allows other and reverse (PTR) resource records can be updated. This allows other
nodes to conveniently refer to a host, despite the fact that its IPv6 nodes to conveniently refer to a host, despite the fact that its IPv6
address may be changing. address may be changing.
This mechanism exposes two important pieces of information: current This mechanism exposes two important pieces of information: the
address (which can be mapped to current location) and client's current address (which can be mapped to current location) and a
hostname. The stable hostname can then by used to correlate the client's hostname. The stable hostname can then by used to correlate
client across different network attachments even when its IPv6 the client across different network attachments even when its IPv6
address keeps changing. address keeps changing.
4.3. Allocation strategies 4.3. Allocation Strategies
A DHCPv6 server running in typical, stateful mode is given a task of A DHCPv6 server running in typical, stateful mode is given a task of
managing one or more pools of IPv6 resources (currently non-temporary managing one or more pools of IPv6 resources (currently non-temporary
addresses, temporary addresses and/or prefixes, but more resource addresses, temporary addresses and/or prefixes, but more resource
types may be defined in the future). When a client requests a types may be defined in the future). When a client requests a
resource, server must pick a resource out of configured pool. resource, the server must pick a resource out of the configured pool.
Depending on the server's implementation, various allocation Depending on the server's implementation, various allocation
strategies are possible. Choices in this regard may have privacy strategies are possible. Choices in this regard may have privacy
implications. implications.
Iterative allocation - a server may choose to allocate addresses one Iterative allocation: a server may choose to allocate addresses one
by one. That strategy has the benefit of being very fast, thus being by one. That strategy has the benefit of being very fast, thus
favored in deployments that prefer performance. However, it makes being favored in deployments that prefer performance. However, it
the resources very predictable. Also, since the resources allocated makes the resources very predictable. Also, since the resources
tend to be clustered at the beginning of an available pool, it makes allocated tend to be clustered at the beginning of an available
scanning attacks much easier. pool, it makes scanning attacks much easier.
Identifier-based allocation - some server implementations use a fixed Identifier-based allocation: some server implementations use a fixed
identifier for a specific client, seemingly taken from the client's identifier for a specific client, seemingly taken from the
MAC address when available or some lower bits of client's source IPv6 client's MAC address when available or some lower bits of client's
address. This has a property of being convenient for converting IP source IPv6 address. This has a property of being convenient for
address to/from other identifiers, especially if the identifier is or converting IP address to/from other identifiers, especially if the
contains MAC address. It is also convenient, as a returning client identifier is or contains a MAC address. It is also convenient,
is very likely to get the same address, even if the server does not as a returning client is very likely to get the same address, even
retain previous client's address. Those properties are convenient if the server does not retain the client's previous address.
for system administrators, so DHCPv6 server implementors are Those properties are convenient for system administrators, so
sometimes requested to implement it. There is at least one DHCPv6 server implementors are sometimes requested to implement
implementation that supports it. The downside of such allocation is it. There is at least one implementation that supports it. The
that the client now discloses its identifier in its IPv6 address to downside of such allocation is that the client now discloses its
all services it connects to. That means that correlation of identifier in its IPv6 address to all services to which it
activities over time, location tracking, address scanning and OS/ connects. That means that attacks related to the correlation of
vendor discovery attacks apply. activities over time, location tracking, address scanning, and OS/
vendor discovery apply.
Hash allocation - it's an extension of identifier-based allocation. Hash allocation: an extension of identifier-based allocation.
Instead of using the identifier directly, it is hashed first. If the Instead of using the identifier directly, it is hashed first. If
hash is implemented correctly, it removes the flaw of disclosing the the hash is implemented correctly, it removes the flaw of
identifier, a property that eliminates susceptibility to address disclosing the identifier, a property that eliminates
scanning and OS/vendor discovery. If the hash is poorly implemented susceptibility to address scanning and OS/vendor discovery. If
(e.g., can be reversed), it introduces no improvement over the hash is poorly implemented (e.g., can be reversed), it
identifier-based allocation. Even a well implemented hash does not introduces no improvement over identifier-based allocation. Even
mitigate the threat of correlation over time. a well-implemented hash does not mitigate the threat of
correlation over time.
Random allocation - a server can pick a resource pseudo-randomly out Random allocation: a server can pick a resource pseudorandomly out
of an available pool. This allocation scheme essentially prevents of an available pool. This allocation scheme essentially prevents
returning clients from getting the same address or prefix again. On returning clients from getting the same address or prefix again.
the other hand, it is beneficial from privacy perspective as On the other hand, it is beneficial from a privacy perspective as
addresses and prefixes generated that way are not susceptible to addresses and prefixes generated that way are not susceptible to
correlation attacks, OS/vendor discovery attacks, or identity correlation attacks, OS/vendor discovery attacks, or identity
discovery attacks. Note that even though the address or prefix discovery attacks. Note that even though the address or prefix
itself may be resilient to a given attack, the client may still be itself may be resilient to a given attack, the client may still be
susceptible if additional information is disclosed other way, e.g., susceptible if additional information is disclosed other way; for
the client's address may be randomized, but it still can leak its MAC example, the client's address may be randomized, but it still can
address in the client-id option. leak its MAC address in the Client Identifier option.
Other allocation strategies may be implemented. Other allocation strategies may be implemented.
5. Attacks 5. Attacks
5.1. Device type discovery (fingerprinting) 5.1. Device Type Discovery (Fingerprinting)
The type of device used by the client can be guessed by the attacker The type of device used by the client can be guessed by the attacker
using the Vendor Class option, Vendor-specific Information option, using the Vendor Class option, Vendor-specific information option,
the Client Link-layer Address option, and by parsing the Client ID the client link-layer address option, and by parsing the Client
option. All of those options may contain OUI (Organizationally Identifier option. All of those options may contain OUI
Unique Identifier) that represents the device's vendor. That (Organizationally Unique Identifier) that represents the device's
knowledge can be used for device-specific vulnerability exploitation vendor. That knowledge can be used for device-specific vulnerability
attacks. See Section 3.4 of exploitation attacks. See Section 3.4 of [RFC7721] for a discussion
[I-D.ietf-6man-ipv6-address-generation-privacy] for a discussion
about this type of attack. about this type of attack.
5.2. Operating system discovery (fingerprinting) 5.2. Operating System Discovery (Fingerprinting)
The operating system running on a client can be guessed using the The operating system running on a client can be guessed using the
Vendor Class option, the Vendor-specific Information option, the Vendor Class option, the Vendor-specific information option, the
Client System Architecture Type option, or by using fingerprinting Client System Architecture Type option, or by using fingerprinting
techniques on the combination of options requested using the Option techniques on the combination of options requested using the Option
Request option. See Section 3.4 of Request option.
[I-D.ietf-6man-ipv6-address-generation-privacy] for a discussion
about this type of attack.
5.3. Finding location information 5.3. Finding Location Information
The physical location information can be obtained by the attacker by The physical location information can be obtained by the attacker by
many means. The most direct way to obtain this information is by many means. The most direct way to obtain this information is by
looking into a message originating from the server that contains the looking into a message originating from the server that contains the
Civic Location or GeoLoc option. It can also be indirectly inferred Civic Location or GeoLoc options. It can also be indirectly inferred
using the Remote ID option, the Interface ID option (e.g., if an using the Remote ID option, the Interface ID option (e.g., if an
access circuit on an Access Node corresponds to a civic location), or access circuit on an Access Node corresponds to a civic location), or
the Subscriber ID option (if the attacker has access to subscriber the Subscriber-ID option (if the attacker has access to subscriber
info). info).
Another way to discover client's physical location is to use Another way to discover a client's physical location is to use
geolocation services. Those services typically map IP prefixes into geolocation services. Those services typically map IP prefixes into
geographical locations. Those services are usually based on known geographical locations. The services are usually based on known
locations of the subnet, so they may reveal client's location as locations of the subnet, so they may reveal a client's location to
precise as they can locate a network it is connected to. They the extent of the network to which it is connected, if they can
usually are not able to discover specific physical location within a locate the network. However, they usually are not able to discover
network. That is not awlays true and it depends on the quality of specific physical location within a network. That is not always true
the apriori information available in the geolocation services and it depends on the quality of the a priori information available
databases. It should be noted that this threat is general to the in the geolocation services databases. It should be noted that this
DHCPv6 mechanism. Regardless of the allocation strategy used by the threat is general to the DHCPv6 mechanism. Regardless of the
DHCPv6 server implementation, the addresses assigned will always allocation strategy used by the DHCPv6 server implementation, the
belong to the subnet the server is configured to manage. Cases of addresses assigned will always belong to the subnet the server is
using ULA (Unique Local Addresses) assigned by the DHCPv6 server are configured to manage. Cases of using ULAs (Unique Local Addresses)
out of scope for this document. assigned by the DHCPv6 server are out of scope for this document.
5.4. Finding previously visited networks 5.4. Finding Previously Visited Networks
When DHCPv6 clients connect to a network, they attempt to obtain the When DHCPv6 clients reconnect to a network, they attempt to obtain
same address they had used before they attached to the network. They the same address they used when they previously attached to that
do this by putting the previously assigned address(es) in the IA network. They do this by putting the previously assigned address(es)
Address option(s). [RFC3315] does not exclude IA_TA in such a case, in the IA Address option(s). [RFC3315] does not exclude IA_TA in
so it is possible that a client implementation includes an address such a case, so it is possible that a client implementation includes
contained in an IA_TA for the Confirm message. By observing these an address contained in an IA_TA for the Confirm message. By
addresses, an attacker can identify the network the client had observing these addresses, an attacker can identify the network the
previously visited. client had previously visited.
5.5. Finding a stable identity 5.5. Finding a Stable Identity
An attacker might use a stable identity gleaned from DHCPv6 messages An attacker might use a stable identity gleaned from DHCPv6 messages
to correlate activities of a given client on unrelated networks. The to correlate activities of a given client on unrelated networks. The
Client FQDN option, the Subscriber ID option, and the Client ID Client FQDN option, the Subscriber-ID option, and the Client ID
option can serve as long-lived identifiers of DHCPv6 clients. The option can serve as long-lived identifiers of DHCPv6 clients. The
Client FQDN option can also provide an identity that can easily be Client FQDN option can also provide an identity that can easily be
correlated with web server activity logs. correlated with web server activity logs.
It should be noted that in general case, the MAC addresses as such It should be noted that in the general case, the MAC addresses as
are not available in the DHCPv6 packets. Therefore they cannot be such are not available in the DHCPv6 packets. Therefore, they cannot
used directly in a reliable way. However, they may become indirectly be used directly in a reliable way. However, they may become
available using other mechanisms: client-id contains link-local indirectly available using other mechanisms: the client-id contains
address if DUID-LL or DUID-LLT types are used, source IPv6 address the link-local address if DUID-LL or DUID-LLT types are used, the
may use EUI-64 that contains MAC address, some access technologies source IPv6 address may use an EUI-64 that contains a MAC address,
may specify MAC address in dedicated options (e.g., cable modems use some access technologies may specify a MAC address in dedicated
MAC addresses in DOCSIS options). Relay agents may insert additional options (e.g., cable modems use MAC addresses in Data Over Cable
information that are used to help the server to identify the client. Service Interface Specification (DOCSIS) options). Relay agents may
This could be Remote-Id option, Subscriber-Id option, client link- insert additional information that is used to help the server to
layer address option or vendor specific information options. Options identify the client. This could be the Remote-Id option, Subscriber-
inserted by relay agents usually traverse only relay-server path, so ID option, client link-layer address option or Vendor-specific
they typically can't be eavesdropped by intercepting client's information options. Options inserted by relay agents usually
transmissions. This depends on the actual deployment model and used traverse only the relay-server path, so they typically can't be
access technologies. eavesdropped by intercepting the client's transmissions. This
depends on the actual deployment model and used access technologies.
5.6. Pervasive monitoring 5.6. Pervasive Monitoring
Pervasive Monitoring (PM) is widespread (and often covert) Pervasive Monitoring (PM) is widespread (and often covert)
surveillance through intrusive gathering of protocol artefacts, surveillance through intrusive gathering of protocol artifacts,
including application content, or protocol metadata such as headers. including application content or protocol metadata such as headers.
Active or passive wiretaps and traffic analysis, (e.g., correlation, Active or passive wiretaps and traffic analysis, (e.g., correlation,
timing or measuring packet sizes), or subverting the cryptographic timing or measuring packet sizes) or subverting the cryptographic
keys used to secure protocols can also be used as part of pervasive keys used to secure protocols can also be used as part of pervasive
monitoring. PM is distinguished by being indiscriminate and very monitoring. PM is distinguished by being indiscriminate and very
large scale, rather than by introducing new types of technical large scale; it does not necessarily introduce new types of technical
compromise. See [RFC7258] for a discussion about PM. compromise. See [RFC7258] for a discussion about PM.
In the DHCPv6 context, PM approach can be used to collect any In the DHCPv6 context, the PM approach can be used to collect any
identifiers discussed in Section 3. DHCPv4 and DHCPv6 are especially identifiers discussed in Section 3. DHCPv4 and DHCPv6 are especially
susceptible as the initial message sent (SOLICIT in case of DHCPv6) susceptible as the initial message sent (SOLICIT in the case of
is one of the very first packets sent when visiting a network. DHCPv6) is one of the very first packets sent when visiting a
Furthermore, in certain cases this packet can be logged even on network. Furthermore, in certain cases, this packet can be logged
networks that do not support IPv6 (some implementations initiate even on networks that do not support IPv6 (some implementations
DHCPv6 even without receiving RA with M or O bits set). This may be initiate DHCPv6 even without receiving RA with M or O bits set).
an easily overlooked attack vector when IPv6-capable device connects This may be an easily overlooked attack vector when an IPv6-capable
to an IPv4 only network, gains only IPv4 connectivity, but still device connects to an IPv4-only network, gains only IPv4
leaks its stable identifiers over DHCPv6. connectivity, but still leaks its stable identifiers over DHCPv6.
Using PM approach, attacks discussed in Sections 5.1, 5.2, 5.3, 5.4, Using the PM approach, the attacks discussed in Sections 5.1, 5.2,
5.5, 5.7, 5.8 and possibly 5.9 apply. 5.3, 5.4, 5.5, 5.7, 5.8, and possibly 5.9, apply.
5.7. Finding client's IP address or hostname 5.7. Finding a Client's IP Address or Hostname
Many DHCPv6 deployments use DNS Updates [RFC4704] that put client's Many DHCPv6 deployments use DNS Updates [RFC4704] that put client's
information (current IP address, client's hostname) into the DNS, information (current IP address, client's hostname) into the DNS,
where it is easily accessible by anyone interested. Client ID is where it is easily accessible by anyone interested. Client ID is
also disclosed, albeit in not easily accessible form (SHA-256 digest also disclosed, albeit in not an easily accessible form (SHA-256
of the client-id). As SHA-256 is considered irreversible, DHCID digest of the client-id). As SHA-256 is considered irreversible,
can't be converted back to client-id. However, SHA-256 digest can be DHCID can't be converted back to client-id. However, SHA-256 digest
used as an unique identifier that is accessible by any host. can be used as an unique identifier that is accessible by any host.
5.8. Correlation of activities over time 5.8. Correlation of Activities over Time
As with other identifiers, an IPv6 address can be used to correlate As with other identifiers, an IPv6 address can be used to correlate
the activities of a host for at least as long as the lifetime of the the activities of a host for at least as long as the lifetime of the
address. If that address was generated from some other, stable address. If that address was generated from some other, stable
identifier and that generation scheme can be deduced by an attacker, identifier and that generation scheme can be deduced by an attacker,
the duration of the correlation attack extends to that of the the duration of the correlation attack extends to that of the
identifier. In many cases, its lifetime is equal to the lifetime of identifier. In many cases, its lifetime is equal to the lifetime of
the device itself. See Section 3.1 of the device itself. See Section 3.1 of [RFC7721] for detailed
[I-D.ietf-6man-ipv6-address-generation-privacy] for detailed
discussion. discussion.
5.9. Location tracking 5.9. Location Tracking
If a stable identifier is used for assigning an address and such If a stable identifier is used for assigning an address and such
mapping is discovered by an attacker (e.g., a server that uses IEEE- mapping is discovered by an attacker (e.g., a server that uses IEEE-
identifier-based IID to generate IPv6 address), all scenarios identifier-based IID to generate an IPv6 address), all scenarios
discussed in Section 3.2 of discussed in Section 3.2 of [RFC7721] apply. In particular, both
[I-D.ietf-6man-ipv6-address-generation-privacy] apply. In particular passive (a service that the client connects to can log the client's
both passive (a service that the client connects to can log the address and draw conclusions regarding its location and movement
client's address and draw conclusions regarding its location and patterns based on the prefix it is connecting from) and active (an
movement patterns based on the prefix it is connecting from) and attacker can send ICMPv6 echo requests or other probe packets to
active (an attacker can send ICMPv6 echo requests or other probe networks of suspected client locations) can be used. To give a
packets to networks of suspected client locations) can be used. To specific example, by accessing a social portal from
give specific example, by accessing a social portal from tomek- tomek-laptop.coffee.somecity.com.example,
laptop.coffee.somecity.com.example, tomek- tomek-laptop.mycompany.com.example, and
laptop.mycompany.com.example and tomek-laptop.myisp.example.com, the tomek-laptop.myisp.example.com, the portal administrator can draw
portal administrator can draw conclusions about tomek-laptop's conclusions about tomek-laptop's owner's current location and his
owner's current location and his habits. habits.
5.10. Leasequery & bulk leasequery 5.10. Leasequery and Bulk Leasequery
Attackers may masquerade to be an access concentrator, either as a Attackers may masquerade as an access concentrator, either as a
DHCPv6 relay agent or as a DHCPv6 client, to obtain location DHCPv6 relay agent or as a DHCPv6 client, to obtain location
information directly from the DHCPv6 server(s) using the DHCPv6 information directly from the DHCPv6 server(s) using the DHCPv6
Leasequery [RFC5007] mechanism. Leasequery [RFC5007] mechanism.
Location information is information needed by the access concentrator Location information is information needed by the access concentrator
to forward traffic to a broadband-accessible host. This information to forward traffic to a broadband-accessible host. This information
includes knowledge of the host hardware address, the port or virtual includes knowledge of the host hardware address, the port or virtual
circuit that leads to the host, and/or the hardware address of the circuit that leads to the host, and/or the hardware address of the
intervening subscriber modem. intervening subscriber modem.
Furthermore, the attackers may use the DHCPv6 bulk leasequery Furthermore, the attackers may use the DHCPv6 bulk leasequery
[RFC5460] mechanism to obtain bulk information about DHCPv6 bindings, [RFC5460] mechanism to obtain bulk information about DHCPv6 bindings,
even without knowing the target bindings. even without knowing the target bindings.
Additionally, active leasequery [RFC7653] is a mechanism for Additionally, active leasequery [RFC7653] is a mechanism for
subscribing to DHCPv6 lease update changes in near real-time. The subscribing to DHCPv6 lease update changes in near real-time. The
intent of this mechanism is to update an operator's database, but if intent of this mechanism is to update an operator's database;
misused, an attacker could defeat the server's authentication however, if the mechanism is misused, an attacker could defeat the
mechanisms and subscribe to all updates. He then could continue server's authentication mechanisms and subscribe to all updates. He
receiving updates, without any need for local presence. then could continue receiving updates, without any need for local
presence.
6. Security Considerations 6. Security Considerations
In current practice, the client privacy and client authentication are In current practice, the client privacy and client authentication are
mutually exclusive. The client authentication procedure reveals mutually exclusive. The client authentication procedure reveals
additional client information in their certificates/identifiers. additional client information in their certificates/identifiers.
Full privacy for the clients may mean the clients are also anonymous Full privacy for the clients may mean the clients are also anonymous
to the server and the network. to the server and the network.
7. Privacy Considerations 7. Privacy Considerations
This document in its entirety discusses privacy considerations in This document in its entirety discusses privacy considerations in
DHCPv6. As such, no dedicated discussion is needed. DHCPv6. As such, no dedicated discussion is needed.
8. IANA Considerations 8. References
This draft does not request any IANA action.
9. Acknowledgements
The authors would like to thank Stephen Farrell, Ted Lemon, Ines
Robles, Russ White, Christian Schaefer, Jinmei Tatuya, Bernie Volz,
Marcin Siodelski, Christian Huitema, Brian Haberman, Robert Sparks,
Peter Yee, Ben Campbell and other members of DHC WG for their
valuable comments.
This document was produced using the xml2rfc tool [RFC7749].
10. References
10.1. Normative References
[I-D.ietf-6man-ipv6-address-generation-privacy] 8.1. Normative References
Cooper, A., Gont, F., and D. Thaler, "Privacy
Considerations for IPv6 Address Generation Mechanisms",
draft-ietf-6man-ipv6-address-generation-privacy-08 (work
in progress), September 2015.
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <http://www.rfc-editor.org/info/rfc3315>. 2003, <http://www.rfc-editor.org/info/rfc3315>.
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973, Considerations for Internet Protocols", RFC 6973,
DOI 10.17487/RFC6973, July 2013, DOI 10.17487/RFC6973, July 2013,
<http://www.rfc-editor.org/info/rfc6973>. <http://www.rfc-editor.org/info/rfc6973>.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
2014, <http://www.rfc-editor.org/info/rfc7258>. 2014, <http://www.rfc-editor.org/info/rfc7258>.
10.2. Informative References [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
Considerations for IPv6 Address Generation Mechanisms",
RFC 7721, DOI 10.17487/RFC7721, March 2016,
<http://www.rfc-editor.org/info/rfc7721>.
8.2. Informative References
[RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)", "Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, DOI 10.17487/RFC2136, April 1997, RFC 2136, DOI 10.17487/RFC2136, April 1997,
<http://www.rfc-editor.org/info/rfc2136>. <http://www.rfc-editor.org/info/rfc2136>.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633, Host Configuration Protocol (DHCP) version 6", RFC 3633,
DOI 10.17487/RFC3633, December 2003, DOI 10.17487/RFC3633, December 2003,
<http://www.rfc-editor.org/info/rfc3633>. <http://www.rfc-editor.org/info/rfc3633>.
skipping to change at page 17, line 22 skipping to change at page 18, line 9
<http://www.rfc-editor.org/info/rfc6422>. <http://www.rfc-editor.org/info/rfc6422>.
[RFC6939] Halwasia, G., Bhandari, S., and W. Dec, "Client Link-Layer [RFC6939] Halwasia, G., Bhandari, S., and W. Dec, "Client Link-Layer
Address Option in DHCPv6", RFC 6939, DOI 10.17487/RFC6939, Address Option in DHCPv6", RFC 6939, DOI 10.17487/RFC6939,
May 2013, <http://www.rfc-editor.org/info/rfc6939>. May 2013, <http://www.rfc-editor.org/info/rfc6939>.
[RFC7653] Raghuvanshi, D., Kinnear, K., and D. Kukrety, "DHCPv6 [RFC7653] Raghuvanshi, D., Kinnear, K., and D. Kukrety, "DHCPv6
Active Leasequery", RFC 7653, DOI 10.17487/RFC7653, Active Leasequery", RFC 7653, DOI 10.17487/RFC7653,
October 2015, <http://www.rfc-editor.org/info/rfc7653>. October 2015, <http://www.rfc-editor.org/info/rfc7653>.
[RFC7749] Reschke, J., "The "xml2rfc" Version 2 Vocabulary", [RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity
RFC 7749, DOI 10.17487/RFC7749, February 2016, Profile for DHCP Clients", RFC 7844, DOI 10.17487/RFC7844,
<http://www.rfc-editor.org/info/rfc7749>. May 2016, <http://www.rfc-editor.org/info/rfc7844>.
Acknowledgements
The authors would like to thank Stephen Farrell, Ted Lemon, Ines
Robles, Russ White, Christian Schaefer, Jinmei Tatuya, Bernie Volz,
Marcin Siodelski, Christian Huitema, Brian Haberman, Robert Sparks,
Peter Yee, Ben Campbell, and other members of DHC WG for their
valuable comments.
Authors' Addresses Authors' Addresses
Suresh Krishnan Suresh Krishnan
Ericsson Ericsson
8400 Decarie Blvd. 8400 Decarie Blvd.
Town of Mount Royal, QC Town of Mount Royal, QC
Canada Canada
Phone: +1 514 345 7900 x42871 Phone: +1 514 345 7900 x42871
Email: suresh.krishnan@ericsson.com Email: suresh.krishnan@ericsson.com
Tomek Mrugalski Tomek Mrugalski
Internet Systems Consortium, Inc. Internet Systems Consortium, Inc.
950 Charter Street 950 Charter Street
Redwood City, CA 94063 Redwood City, CA 94063
USA United States
Email: tomasz.mrugalski@gmail.com Email: tomasz.mrugalski@gmail.com
Sheng Jiang Sheng Jiang
Huawei Technologies Co., Ltd Huawei Technologies Co., Ltd.
Q14, Huawei Campus, No.156 BeiQing Road Q14, Huawei Campus, No.156 BeiQing Road
Hai-Dian District, Beijing 100095 Hai-Dian District, Beijing 100095
P.R. China China
Email: jiangsheng@huawei.com Email: jiangsheng@huawei.com
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