APNIC Training

eDNS02: Reverse DNS for IPv4 and IPv6

DeliveryeLearning (this course is conducted online)
Duration1 hour
Level of StudyIntermediate


Reverse DNS allows the mapping of a domain name from an IP address. This is achieved by the use of pseudo-domain names under in-addr.arpa (IPv4) and ip6.arpa (IPv6). For all IP address blocks that IANA (the Internet Assigned Numbers Authority) allocates to APNIC, it also delegates corresponding reverse DNS zones within the centrally administered "in-addr.arpa" and "ip6.arpa" domains.

This course will focus on the concepts of Reverse DNS as well as the procedures for managing these reverse delegations.

Target Audience:

This course is aimed at systems administrators and those involved in DNS operations.


Basic knowledge of networking and Unix/Linux. It is recommended that participants attend the eDNS01 course prior to attending this course.

Course Outline:

  • What is Reverse DNS?
  • Principles of DNS Tree
  • Creating Reverse Zones
  • Pointer (PTR) Records
  • IPv6 Reverse Lookups
  • Reverse delegation requirements
  • APNIC & ISPs responsibilities
  • Reverse Delegation Procedures
  • Whois domain object

Other requirements:

  • Updated web browser with Adobe Flash Player 11 or above
  • Broadband connection running at a minimum of 256kbps or better
  • Headset (to reduce noise)

Maximum number of attendees:

50 participants per session


  • Free

All eLearning courses are free of charge for participants, with priority given to APNIC Members.

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Download slides for this course (979.7 KB).