RFC 2181 (rfc2181) - Page 1 of 15
Clarifications to the DNS Specification
Alternative Format: Original Text Document
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.
Elz & Bush Standards Track
