DNSEXT Working Group Lianyuan Li, Internet-Draft Zhenqiang Li, Intended status: Informational Xiaodong Duan, Expires: April 13, 2010 China Mobile October 26, 2009 DNS Extensions to Support IPv4 and IPv6 draft-li-dnsext-ipv4-ipv6-02.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on January 13, 2010. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Li Expires January 13, 2010 [Page 1] Internet-Draft DNS Extensions to Support IPv4 and IPv6 October 2009 Abstract In the DNS architecture, two kinds of record types for maintaining host's IP addresses are supported: one is A type which records IPv4 and AAAA for IPv6 addresses. This document defines a new TYPE, which is mainly used in queries in order to get both IPv4 and IPv6 addresses. The main advantage is to avoid sending several requests in order to resolve the location of a given resource. A single request may be sufficient. The proposed solution does not require the definition of any new record type. Li Expires April 13, 2010 [Page 2] Internet-Draft DNS Extensions to Support IPv4 and IPv6 October 2009 1. Introduction 1.1 Current DNS operation There are mainly two resource record types to store IP addresses in the DNS system. One is A resource record, the other is AAAA resource record. An A resource record is defined to store an IPv4 address, an AAAA is defined to store an IPv6 address. 1.2 Problem for current IPv6 DNS operation Due to large-scale applicable for IPv4, it will take a long time to fully transit from IPv4 to IPv6. During the transition period, IPv4 network and IPv6 network will coexist.In most cases, the host will not know whether the address of the other side is IPv4 or IPv6. According to current practices, the host will send an AAAA query first. If there no IPv6 address has been retrieved, then an A query will be issued. The above mechanism has following disadvantages. 1- It takes longer time to compare with only A or AAAA query which is needed. 2- Both A and AAAA queries will waste bandwidth, especially the air interface bandwidth. 3- More process resources in host and DNS server are needed. In order to solve the above problems, a new kind of query type is proposed. 2. New query type definition A new query type mainly used in queries is defined to get all available addresses (including IPv4 and IPv6). It is not intended to create new resource record. 2.1 v4v6 query type The v4v6 query type is specific to the Internet class. 2.2 v4v6 data format No new data format is defined. In fact, it is unnecessary to create new data format. 2.3 v4v6 query Li Expires April 13, 2010 [Page 3] Internet-Draft DNS Extensions to Support IPv4 and IPv6 October 2009 A v4v6 query for a specified domain name in the Internet class returns all associated A and AAAA resource records in the answer section of a response. 2.4 Textual format of v4v6 query type There is no new textual format for v4v6 query type. 3. Modifications to existing query types All existing query types that perform type A and AAAA processing must be updated to perform type A, type AAAA and v4v6 processing. These definitions mean that a name server must add relevant IPv4 addresses and relevant IPv6 addresses available locally to the response when processing v4v6 queries. 4. Security Considerations Any information obtained from the DNS must be regarded as unsafe unless there are some new security mechanism. The definition of the v4v6 query type does not change the model for use of these techniques. So, this specification is not believed to cause any new security problem. Dedicated means to secure DNS communication should be encouraged. 5. IANA Considerations A record TYPE is to be assigned by IANA. 6. References [1] Mockapetris.P, "Domain Names - Concepts and Facilities", STD 13,RFC 1034, November 1987. [2] Mockapetris.P,, "Domain Names - Implementation and Specification", STD 13, RFC 1035, November 1987. [3] Thomson.S, Huitema.C, Ksinant.V, Souissi.M, "DNS Extensions to Support IP Version 6", RFC 3596, October 2003 Li Expires April 13, 2010 [Page 4] Internet-Draft DNS Extensions to Support IPv4 and IPv6 October 2009 Author's Addresses Lianyuan Li China Mobile Unit 2, 28 Xuanwumenxi Ave, Xuanwu District, Beijing 100053, China Email: lilianyuan@chinamobile.com Zhenqiang Li China Mobile Unit 2, 28 Xuanwumenxi Ave, Xuanwu District, Beijing 100053, China Email: lizhenqiang@chinamobile.com Xiaodong Duan China Mobile Unit 2, 28 Xuanwumenxi Ave, Xuanwu District, Beijing 100053, China Email: duanxiaodong@chinamobile.com Li Expires April 13, 2010 [Page 5]