Registration Data Access Protocol

The Registration Data Access Protocol (RDAP)  is an alternative to WHOIS for accessing Internet resource registration data.  RDAP is designed to address a number of shortcomings in the existing Whois service. The most important changes are:

  • Standardization of queries and responses
  • Internationalization considerations to cater for languages other than English in data objects
  • Redirection capabilities to allow seamless referrals to other registries

Read more about the origin and reasons behind this work and the history of Whois in the APNIC News article, “The Future of Whois”, May 2012.

Using RDAP

APNIC has an RDAP service available on the host.  An example response can be found at:

Replacing the network address portion of the URL will provide registration information for other network addresses, for both IPv4 and IPv6, and for single addresses or for CIDR network blocks.  RDAP also supports autonomous system number lookups via the /autnum/ path prefix.

ARIN are hosting an open source community project for a command line tool to retrieve RDAP records, called NicInfo.  This tool can be used to query RDAP services of both Internet number and domain name registries.

RDAP specifications

RDAP is specified as a suite Internet Request for Comments (RFC) documents.

  1. RFC 7480 – HTTP Usage in the Registration Data Access Protocol (RDAP)
  2. RFC 7481 – Security Services for the Registration Data Access Protocol (RDAP)
  3. RFC 7482 – Registration Data Access Protocol (RDAP) Query Format
  4. RFC 7483 – JSON Responses for the Registration Data Access Protocol (RDAP)
  5. RFC 7484 – Finding the Authoritative Registration Data (RDAP) Service
  6. RFC 7485 – Inventory and Analysis of WHOIS Registration Objects