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.
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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...