Network Working Group P. Spacek Internet-Draft CZ.NIC Intended status: Standards Track O. Gudmundsson Expires: November 30, 2018 Cloudflare O. Sury ISC May 29, 2018 Minimal EDNS compliance requirements draft-spacek-edns-camel-diet-01 Abstract DNS responders must either follow RFC 6891 by fully implementing EDNS or at least respond to queries containing OPT record according to older specifications. Non-compliant implementations which do not respond at all are not worth talking to. 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 November 30, 2018. Copyright Notice Copyright (c) 2018 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 Spacek, et al. Expires November 30, 2018 [Page 1] Internet-Draft Minimal EDNS compliance May 2018 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 2. The Protocol . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Security Considerations . . . . . . . . . . . . . . . . . . . 2 4. Privacy Considerations . . . . . . . . . . . . . . . . . . . 2 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 6. Normative References . . . . . . . . . . . . . . . . . . . . 3 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction Neither the original DNS standard RFC 1035 nor its extensions RFC 2671 and RFC 6891 allow not to respond to a DNS query. Many years later non-compliant implementations which drop queries still exist and cause lot of extra queries, latency, and complicated logic in recursive resolvers. The cost of supporting these non-compliant implementations keeps increasing. 1.1. Terminology 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 RFC 2119. 2. The Protocol No DNS response message to a repeated DNS query containing EDNS extension implies that the other side is not a DNS responder. The querier MUST NOT retry its query without EDNS. 3. Security Considerations Instruction to follow EDNS standard does not change security properties beyond what is written in RFC 6891. 4. Privacy Considerations This has no effect on privacy of DNS. Spacek, et al. Expires November 30, 2018 [Page 2] Internet-Draft Minimal EDNS compliance May 2018 5. IANA Considerations [Note to IANA, to be removed prior to publication: there are no IANA considerations stated in this version of the document.] 6. Normative References [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, November 1987, . [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC 2671, DOI 10.17487/RFC2671, August 1999, . [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms for DNS (EDNS(0))", STD 75, RFC 6891, DOI 10.17487/RFC6891, April 2013, . Authors' Addresses Petr Spacek Email: petr.spacek@nic.cz Olafur Gudmundsson Email: olafur+ietf@cloudflare.com Ondrej Sury Email: ondrej@isc.org Spacek, et al. Expires November 30, 2018 [Page 3]