Privacy Considerations for DHCP
RFC 7819
Internet Engineering Task Force (IETF) S. Jiang
Request for Comments: 7819 Huawei Technologies Co., Ltd
Category: Informational S. Krishnan
ISSN: 2070-1721 Ericsson
T. Mrugalski
ISC
April 2016
Privacy Considerations for DHCP
Abstract
DHCP is a protocol that is used to provide addressing and
configuration information to IPv4 hosts. This document discusses the
various identifiers used by DHCP and the potential privacy issues.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
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.
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/rfc7819.
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Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Jiang, et al. Informational [Page 1]
RFC 7819 DHCP Privacy Considerations April 2016
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language and Terminology . . . . . . . . . . . . 3
3. DHCP Options Carrying Identifiers . . . . . . . . . . . . . . 4
3.1. Client Identifier Option . . . . . . . . . . . . . . . . 4
3.2. Address Fields and Options . . . . . . . . . . . . . . . 4
3.3. Client FQDN Option . . . . . . . . . . . . . . . . . . . 5
3.4. Parameter Request List Option . . . . . . . . . . . . . . 5
3.5. Vendor Class and Vendor-Identifying Vendor Class Options 5
3.6. Civic Location Option . . . . . . . . . . . . . . . . . . 6
3.7. Coordinate-Based Location Option . . . . . . . . . . . . 6
3.8. Client System Architecture Type Option . . . . . . . . . 6
3.9. Relay Agent Information Option and Suboptions . . . . . . 6
4. Existing Mechanisms That Affect Privacy . . . . . . . . . . . 7
4.1. DNS Updates . . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Allocation Strategies . . . . . . . . . . . . . . . . . . 7
5. Attacks . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. Device Type Discovery . . . . . . . . . . . . . . . . . . 9
5.2. Operating System Discovery . . . . . . . . . . . . . . . 9
5.3. Finding Location Information . . . . . . . . . . . . . . 9
5.4. Finding Previously Visited Networks . . . . . . . . . . . 9
5.5. Finding a Stable Identity . . . . . . . . . . . . . . . . 9
5.6. Pervasive Monitoring . . . . . . . . . . . . . . . . . . 10
5.7. Finding Client's IP Address or Hostname . . . . . . . . . 10
5.8. Correlation of Activities over Time . . . . . . . . . . . 10
5.9. Location Tracking . . . . . . . . . . . . . . . . . . . . 10
5.10. Leasequery and Bulk Leasequery . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 12
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
Jiang, et al. Informational [Page 2]
RFC 7819 DHCP Privacy Considerations April 2016
1. Introduction
The Dynamic Host Configuration Protocol (DHCP) [RFC2131] is used to
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