Current issues with DNS Configuration Options for SLAAC
draft-gont-6man-slaac-dns-config-issues-01

Document Type Active Internet-Draft (individual)
Last updated 2015-02-26
Stream (None)
Intended RFC status (None)
Formats plain text pdf html
Stream Stream state (No stream defined)
Document shepherd No shepherd assigned
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
IPv6 maintenance Working Group (6man)                            F. Gont
Internet-Draft                                    SI6 Networks / UTN-FRH
Updates: 6106 (if approved)                                   P. Simerda
Intended status: Standards Track
Expires: August 30, 2015                                          W. Liu
                                                     Huawei Technologies
                                                       February 26, 2015

        Current issues with DNS Configuration Options for SLAAC
               draft-gont-6man-slaac-dns-config-issues-01

Abstract

   RFC 6106 specifies two Neighbor Discovery options that can be
   included in Router Advertisement messages to convey information about
   DNS recursive servers and DNS Search Lists.  Small lifetime values
   for the aforementioned options have been found to cause
   interoperability problems in those network scenarios in which these
   options are used to convey DNS-related information.  This document
   analyzes the aforementioned problem, and formally updates RFC 6106
   such that these issues are mitigated.

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 http://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 August 30, 2015.

Copyright Notice

   Copyright (c) 2015 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
   (http://trustee.ietf.org/license-info) in effect on the date of

Gont, et al.             Expires August 30, 2015                [Page 1]
Internet-Draft       SLAAC DNS Configuration Issues        February 2015

   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.  Changing the Semantics of the 'Lifetime' field of RDNSS and
       DNSSL options . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Changing the Default Values of the 'Lifetime' field of RDNSS
       and DNSSL options . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Use of Router Solicitations for active Probing  . . . . . . .   4
   5.  Sanitize the received RDNSS/DNSSL 'Lifetime' Values . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   RFC 6106 [RFC6106] specifies two Neighbor Discovery (ND) [RFC4861]
   options that can be included in Router Advertisement messages to
   convey information about DNS recursive servers and DNS Search Lists.
   Namely, the Recursive DNS Server (RDNSS) Option specifies the IPv6
   addresses of recursive DNS servers, while the DNS Search List (DNSSL)
   Option specifies a "search list" to be used when trying to resolve a
   name by means of the DNS.

   Each of this options include a "Lifetime" field which specifies the
   maximum time, in seconds, during which the information included in
   the option can be used by the receiving system.  The aforementioned
   "Lifetime" value is set as a function of the Neighbor Discovery
   parameter 'MaxRtrAdvInterval', which specifies the maximum time
   allowed between sending unsolicited multicast Router Advertisements
   from an interface.  The recommended bounds (MaxRtrAdvInterval <=
   Lifetime <= 2*MaxRtrAdvInterval) have been found to be too short for
   scenarios in which some Router Advertisement messages may be lost.
   In such scenarios, hosts may fail to receive unsolicited Router
   Advertisements and therefore fail to refresh the expiration time of
Show full document text