Dprive Working Group Z. Yan Internet-Draft CNNIC Intended status: Standards Track G. Geng Expires: June 16, 2021 Jinan University Y. Liu CAICT X. Zhang Shandong Computer Science Center X. Zhu Shandong Institute of Big Data December 13, 2020 Indication of Local DNS Privacy Service During User Access draft-yan-dprive-local-service-indication-04 Abstract This document aims to support the indication of privacy service capability of recursive resolver during the end-user accesses the network. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL","SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. 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 https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on June 16, 2021. Yan, et al. Expires June 16, 2021 [Page 1] Internet-Draft Indication of DNS Privacy Service December 2020 Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. ICMPv6 based case . . . . . . . . . . . . . . . . . . . . . . 2 3. DHCPv6 based case . . . . . . . . . . . . . . . . . . . . . . 3 4. Security considerations . . . . . . . . . . . . . . . . . . . 3 5. Normative References . . . . . . . . . . . . . . . . . . . . 4 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction In order to enhance the privacy protection in DNS, several solutions have been developed to support the encrypted communications between stub and recursive resolvers, such as DNS-over-DTLS [RFC8094], DNS- over-TLS [RFC7858], DNS-over-QUIC and so on. However, a scheme is needed in order to explicitly make the end-user (stub resovler) be aware of the types of privacy service supported by the recursive resolver in order to avoid the blind attempt by the end-user and support the user to bootstrap the preferred privacy protocol more easily. This can be achieved during the user initial access, using extended DHCPv6 or ICMPv6 to configure its recursive resolver with related information (only IPv6 scenario is considered herein). 2. ICMPv6 based case The "Recursive DNS Server Option" is defined in [RFC8106] to support the user to configure DNS recursive resolver in the IPv6 SLAAC mode. Then a 4-bit (for example) space (denoted as "Cap." field) in the Reserved field of "Recursive DNS Server Option" can be used to indicate the privacy service of the corresponding recursive resolver specified in the field of "Addresses of IPv6 Recursive DNS Servers". However, if this function is used, the "Addresses of IPv6 Recursive Yan, et al. Expires June 16, 2021 [Page 2] Internet-Draft Indication of DNS Privacy Service December 2020 DNS Servers" should contain only the recursive resolver(s) with the same privacy service capability indicated by the corresponding "Cap." field. How to code the "Cap." field will be detailed further. 3. DHCPv6 based case The "DNS Recursive Name Server option" is defined in [RFC3646] to support the user to configure DNS recursive resolver in the IPv6 DHCP [RFC4339] mode. However, [RFC3646] did not reserve extra space, a new option should be defined which is conjunctively used with "DNS Recursive Name Server option". It is defined as "DNS Recursive Server Privacy option" and the format is shown in Figure 1. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_DNS_SERVERS_PRIVACY | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cap. | Cap. |...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: DNS Recursive Server Privacy option o option-code: OPTION_DNS_SERVERS_PRIVACY o option-len: Length of the list of privacy service capability of DNS recursive name servers in octets; must be a multiple of 4 (for example). o Capability: The 4-bit (for example) space (denoted as "Cap." field) is used to indicate the privacy service of the corresponding recursive resolver specified in the field of DNS- recursive-name-server in the DNS Recursive Name Server option. The DNS Recursive Server Privacy option should be used conjunctively with the DNS Recursive Name Server option and the order of "Cap." fields in the DNS Recursive Server Privacy option must be corresponding to the server order specified in the DNS Recursive Name Server option. 4. Security considerations TBA Yan, et al. Expires June 16, 2021 [Page 3] Internet-Draft Indication of DNS Privacy Service December 2020 5. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, DOI 10.17487/RFC3646, December 2003, . [RFC4339] Jeong, J., Ed., "IPv6 Host Configuration of DNS Server Information Approaches", RFC 4339, DOI 10.17487/RFC4339, February 2006, . [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., and P. Hoffman, "Specification for DNS over Transport Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 2016, . [RFC8094] Reddy, T., Wing, D., and P. Patil, "DNS over Datagram Transport Layer Security (DTLS)", RFC 8094, DOI 10.17487/RFC8094, February 2017, . [RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, "IPv6 Router Advertisement Options for DNS Configuration", RFC 8106, DOI 10.17487/RFC8106, March 2017, . Yan, et al. Expires June 16, 2021 [Page 4] Internet-Draft Indication of DNS Privacy Service December 2020 Appendix A. Acknowledgments This work was supported by Beijing Nova Program of Science and Technology under grant Z191100001119113. Authors' Addresses Zhiwei Yan CNNIC No.4 South 4th Street, Zhongguancun Beijing 100190 China EMail: yan@cnnic.cn Guanggang Geng Jinan University No.601, West Huangpu Avenue Guangzhou 510632 China EMail: gggeng@jnu.edu.cn Yang Liu CAICT No.52, Huayuanbeilu Beijing 100191 China EMail: liuyang7@caict.ac.cn Xinchang Zhang Shandong Computer Science Center No.19 Keyuan Road, Lixia District Jinan, 250014 P.R. China EMail: xincha.zhang@gmail.com Yan, et al. Expires June 16, 2021 [Page 5] Internet-Draft Indication of DNS Privacy Service December 2020 Xiaomin Zhu Shandong Institute of Big Data 7/F, building 7, Shun Tai Plaza, No.2000, Shun Hua Road, hi-tech Zone Jinan, 250014 P.R. China EMail: zhuxiaomin@ict.ac.cn Yan, et al. Expires June 16, 2021 [Page 6]