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Clarifications to the DNS Specification (RFC2181)

IP.com Disclosure Number: IPCOM000002740D
Original Publication Date: 1997-Jul-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 12 page(s) / 35K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

R. Elz: AUTHOR [+2]

Abstract

This document considers some areas that have been identified as problems with the specification of the Domain Name System, and proposes remedies for the defects identified. Eight separate issues are considered:

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This is the abbreviated version, containing approximately 8% of the total text.

Network Working Group R. Elz

Request for Comments: 2181 University of Melbourne

Updates: 1034, 1035, 1123 R. Bush

Category: Standards Track RGnet, Inc.

July 1997

Clarifications to the DNS Specification

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.

1. Abstract

This document considers some areas that have been identified as

problems with the specification of the Domain Name System, and

proposes remedies for the defects identified. Eight separate issues

are considered:

+ IP packet header address usage from multi-homed servers,

+ TTLs in sets of records with the same name, class, and type,

+ correct handling of zone cuts,

+ three minor issues concerning SOA records and their use,

+ the precise definition of the Time to Live (TTL)

+ Use of the TC (truncated) header bit

+ the issue of what is an authoritative, or canonical, name,

+ and the issue of what makes a valid DNS label.

The first six of these are areas where the correct behaviour has been

somewhat unclear, we seek to rectify that. The other two are already

adequately specified, however the specifications seem to be sometimes

ignored. We seek to reinforce the existing specifications.

Contents

1 Abstract ................................................... 1

2 Introduction ............................................... 2

3 Terminology ................................................ 3

4 Server Reply Source Address Selection ...................... 3

5 Resource Record Sets ....................................... 4

6 Zone Cuts .................................................. 8

7 SOA RRs .................................................... 10

8 Time to Live (TTL) ......................................... 10

9 The TC (truncated) header bit .............................. 11

10 Naming issues .............................................. 11

11 Name syntax ................................................ 13

12 Security Considerations .................................... 14

13 References .........................................