Algorithms for Domain Name System (DNS) Cookies construction
draft-sury-toorop-dns-cookies-algorithms-00

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Last updated 2019-03-11
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DNSOP Working Group                                              O. Sury
Internet-Draft                               Internet Systems Consortium
Updates: 7873 (if approved)                                    W. Toorop
Intended status: Standards Track                              NLnet Labs
Expires: September 12, 2019                               March 11, 2019

      Algorithms for Domain Name System (DNS) Cookies construction
              draft-sury-toorop-dns-cookies-algorithms-00

Abstract

   [RFC7873] left the construction of Server Cookies to the discretion
   of the DNS Server (implementer) which has resulted in a gallimaufry
   of different implementations.  As a result, DNS Cookies are
   impractical to deploy on multi-vendor anycast networks, because the
   Server Cookie constructed by one implementation cannot be validated
   by another.

   This document provides precise directions for creating Server Cookies
   to address this issue.  Furthermore, [FNV] is obsoleted as a suitable
   Hash function for calculating DNS Cookies.  [SipHash-2.4] is
   introduced as a new REQUIRED Hash function for calculating DNS
   Cookies.

   This document updates [RFC7873]

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
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 12, 2019.

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Copyright Notice

   Copyright (c) 2019 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Contents of this document . . . . . . . . . . . . . . . .   3
     1.2.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Constructing a Client Cookie  . . . . . . . . . . . . . . . .   3
   3.  Constructing a Server Cookie  . . . . . . . . . . . . . . . .   3
     3.1.  The Version Sub-Field . . . . . . . . . . . . . . . . . .   4
     3.2.  The Cookie algo Sub-Field . . . . . . . . . . . . . . . .   4
     3.3.  The Reserved Sub-Field  . . . . . . . . . . . . . . . . .   4
     3.4.  The Timestamp Sub-Field . . . . . . . . . . . . . . . . .   4
     3.5.  The Hash Sub-Field  . . . . . . . . . . . . . . . . . . .   5
   4.  Cookie Algorithms . . . . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   In [RFC7873] in Section 6 it is "RECOMMENDED for simplicity that the
   Same Server Secret be used by each DNS server in a set of anycast
   servers."  However, how precisely a Server Cookie is calculated from
   this Server Secret, is left to the implementation.

   This guidance has let to DNS Cookie implementations, calculating the
   Server Cookie in different ways.  This causes problems with anycast
   deployments with DNS Software from multiple vendors, because even
   when all DNS Software would share the same secret, as RECOMMENDED in
   Section 6.  of [RFC7873], they all produce different Server Cookies
   based on that secret and (at least) the Client Cookie and Client IP
   Address.

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1.1.  Contents of this document

   In Section Section 2 instructions for constructing a Client Cookie
   are given

   In Section Section 3 instructions for constructing a Server Cookie
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