Network Working Group T. T. Sajitha Internet-Draft Hewlett-Packard Expires: Aug 28, 2004 27 Feb 2003 DNS QTYPE to retrieve IPv4 and IPv6 address draft-sajitha-dnsext-qtype-addr-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 Aug 28, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document proposes a new query type to be used in the DNS [RFC1035] implementation. This is used to retrieve all the IPv4 as well as IPv6 addresses of a host using a single query. 1. Introduction Currently there is no mechanism to get all the v4 and v6 addresses of a host with a single query. This proposal defines a new query type "ADDR" which can be used by a client while querying the DNS server. While processing this query type, the server should return all the records of type T_A & T_AAAA for the QNAME in question, in the answer section of the response. Sajitha Expires Aug 28, 2004 [Page 1]
Internet-Draft DNS QTYPE to retrieve IPv4 and IPv6 address Feb 2003 2. Rationale In DNS IPv4 address is identified by the RR type T_A and IPv6 address by T_AAAA. As the IPv6 deployment is increasing, the dual stack implementations are becoming more common. In this case each hosts will have IPv4 as well as IPv6 address. This calls for the need of retrieving all the v4 as well as v6 address for a particular host. Currently this is achieved by using more than one queries. Most of the internet services need to know the addresses of a host inorder to communicate with it. When DNS is used for address resolution, the queries and responses has to travel over the network and so the time taken to resolve the address of a host becomes very critical. 3. The ADDR qtype The ADDR query type is defined with mnemonic ADDR and type code [TBD]. This is defined for the IN class. Using this query type, client can request for all the addresses of a host using a single query. While processing this query type, the server should return all the records of type T_A & T_AAAA for the host in question. All these records should be provided in the answer section of the response. The server may order all the T_AAAA types first and followed by T_A types. A6 record type is not considered as it is deprecated. 4. Advantage over "ALL" QTYPE The query type denoted by "*" with a value of 255 [see RFC1035 Section 3.2.3] will cause the server to return all types of records corresponding to the QNAME in question. This include A, NS, MX, SOA, CNAME, HINFO etc. For a client looking for the addresses of a host, it is inefficient to process all these records and choose the T_A and T_AAAA. For a DNS server, it has to provide all the RR types of the QNAME if queried with "ALL" QTYPE. This is an overhead to the server. Moreover the DNS packet size will be a limitation to provide all the types of records in a response. Sajitha Expires Aug 28, 2004 [Page 2]
Internet-Draft DNS QTYPE to retrieve IPv4 and IPv6 address Feb 2003 5. Operational Consideration The existing clients can be easily modified to use this QTYPE and if does not get an answer, fall back to the two query sequence as they do now. The old servers which does not support this query type, will return a not implemented RCODE whereas the servers which supports this query type will return the T_A and T_AAAA RRs. 6. Security consideration The ADDR query type as such does not introduce any new security problems into the DNS. 7 - References [RFC1035] P. Mockapetris, ``Domain Names - Implementation and Specification,'' RFC 1035, USC/Information Sciences Institute, November 1987. 8. IANA Considerations IANA is requested to allocate a QTYPE value for the ADDR query type. Author's Address Sajitha T. T. Hewlett-Packard STSD-I 29, Cunningham Road Bangalore - 560052 India Phone: +91-80-2053091 E-Mail: firstname.lastname@example.org Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. Sajitha Expires Aug 28, 2004 [Page 3]
Internet-Draft DNS QTYPE to retrieve IPv4 and IPv6 address Feb 2003 The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society.