RFC 4592 - The Role of Wildcards in the Domain Name System

Network Working Group
Request for Comments: 4592
Updates: 1034, 2672
Category: Standards Track

E. Lewis
NeuStar
July 2006

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 (2006).

Abstract

This is an update to the wildcard definition of RFC 1034. The interaction with wildcards and CNAME is changed, an error condition is removed, and the words defining some concepts central to wildcards are changed. The overall goal is not to change wildcards, but to refine the definition of RFC 1034.

Contents

• 1. Introduction
  • 1.1 Motivation
  • 1.2 The Original Definition
  • 1.3 Roadmap to This Document
    • 1.3.1 New Terms
    • 1.3.2 Changed Text
    • 1.3.3 Considerations with Special Types
  • 1.4 Standards Terminology
• 2. Wildcard Syntax
  • 2.1 Identifying a Wildcard
    • 2.1.1 Wildcard Domain Name and Asterisk Label
    • 2.1.2 Asterisks and Other Characters
    • 2.1.3 Non-terminal Wildcard Domain Names
  • 2.2 Existence Rules
    • 2.2.1 An Example
    • 2.2.2 Empty Non-terminals
    • 2.2.3 Yet Another Definition of Existence
  • 2.3 When Is a Wildcard Domain Name Not Special?
• 3. Impact of a Wildcard Domain Name on a Response
  • 3.1 Step 2
  • 3.2 Step 3
  • 3.3 Part 'c'
    • 3.3.1 Closest Encloser and the Source of Synthesis
    • 3.3.2 Closest Encloser and Source of Synthesis Examples
    • 3.3.3 Type Matching
• 4. Considerations with Special Types
  • 4.1 SOA RRSet at a Wildcard Domain Name
  • 4.2 NS RRSet at a Wildcard Domain Name
    • 4.2.1 Discarded Notions
  • 4.3 CNAME RRSet at a Wildcard Domain Name
  • 4.4 DNAME RRSet at a Wildcard Domain Name
  • 4.5 SRV RRSet at a Wildcard Domain Name
  • 4.6 DS RRSet at a Wildcard Domain Name
  • 4.7 NSEC RRSet at a Wildcard Domain Name
  • 4.8 RRSIG at a Wildcard Domain Name
  • 4.9 Empty Non-terminal Wildcard Domain Name
• 5. Security Considerations
• 6. References
  • 6.1 Normative References
  • 6.2 Informative References
• 7. Others Contributing to the Document
• Full Copyright Statement
• Intellectual Property
• Acknowledgement