APNIC Training

eDNS02: Reverse DNS Delegation Procedures

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


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

This eLearning course will focus on the concepts of Reverse DNS as well as the procedures on how to manage these reverse delegations.

Target Audience:

This course is designed for network engineers, systems administrators, and anyone who is involved in DNS operations.


Basic knowledge of Networking, Unix/Linux

It is recommended that the participants attend eDNS01 course prior to attending this course.

Course Outline:

  • What is 'Reverse DNS'?
  • DNS & Reverse DNS trees
  • Creating reverse zones
  • Start of Authority (SOA) record
  • IPv6 Reverse Lookups – PTR records
  • A reverse zone example
  • 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).