Asia Pacific Network Information Centre American Registry for Internet Numbers The Registration Data Access Protocol (RDAP) is used by Regional Internet Registries (RIRs) and Domain Name Registries (DNRs) to provide access to their resource registration information. The core specifications for RDAP define basic search functionality, but there are various IP and ASN-related search options provided by RIRs via their Whois services for which there is no corresponding RDAP functionality. This document extends RDAP to support those search options.