Browse Prior Art Database

Obsoleting IQUERY (RFC3425)

IP.com Disclosure Number: IPCOM000010305D
Original Publication Date: 2002-Nov-01
Included in the Prior Art Database: 2002-Nov-20
Document File: 6 page(s) / 9K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Lawrence: AUTHOR

Abstract

The IQUERY method of performing inverse DNS lookups, specified in RFC 1035, has not been generally implemented and has usually been operationally disabled where it has been implemented. Both reflect a general view in the community that the concept was unwise and that the widely-used alternate approach of using pointer (PTR) queries and reverse-mapping records is preferable. Consequently, this document deprecates the IQUERY operation, declaring it entirely obsolete. This document updates RFC 1035.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 33% of the total text.

Network Working Group                                        D. Lawrence

Request for Comments: 3425                                       Nominum

Updates: 1035                                              November 2002

Category: Standards Track

                           Obsoleting IQUERY

Status of this Memo

   This document specifies an Internet standards track protocol for the

   Internet community, and requests discussion and suggestions for

   improvements.  Please refer to the current edition of the "Internet

   Official Protocol Standards" (STD 1) for the standardization state

   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   The IQUERY method of performing inverse DNS lookups, specified in RFC

   1035, has not been generally implemented and has usually been

   operationally disabled where it has been implemented.  Both reflect a

   general view in the community that the concept was unwise and that

   the widely-used alternate approach of using pointer (PTR) queries and

   reverse-mapping records is preferable.  Consequently, this document

   deprecates the IQUERY operation, declaring it entirely obsolete.

   This document updates RFC 1035.

1 - Introduction

   As specified in RFC 1035 (section 6.4), the IQUERY operation for DNS

   queries is used to look up the name(s) which are associated with the

   given value.  The value being sought is provided in the query's

   answer section and the response fills in the question section with

   one or more 3-tuples of type, name and class.

   As noted in [RFC1035], section 6.4.3, inverse query processing can

   put quite an arduous burden on a server.  A server would need to

   perform either an exhaustive search of its database or maintain a

   separate database that is keyed by the values of the primary

   database.  Both of these approaches could strain system resource use,

   particularly for servers that are authoritative for millions of

   names.

Lawrence                    Standards Track                     [Page 1]

RFC 3425                   Obsoleting IQUERY               November 2002

   Response packets from these megaservers could be exceptionally large,

   and easily run into megabyte sizes.  For example, using IQUERY to

   find every domain that is delegated to one of the nameservers of a

   large ISP could return tens of thousands of 3-tuples in the question

   section.  This could easily be used to launch denial of service

   attacks.

   Operators of servers that do support IQUERY in some form (such as

   very old BIND 4 servers) generally opt to disable it.  This is

   largely due to bugs in insufficiently-exercised co...