The Registration Data Access Protocol (RDAP) is a

computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...

communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchr ...

standardized by a working group at the

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...

in 2015, after experimental developments and thorough discussions. It is a successor to the

WHOIS WHOIS (pronounced as the phrase "who is") is a query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block or an autonomou ...

protocol, used to look up relevant registration data from such Internet resources as

domain name A domain name is a string that identifies a realm of administrative autonomy, authority or control within the Internet. Domain names are often used to identify services provided through the Internet, such as websites, email services and more. As ...

IP address An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...

es, and

autonomous system numbers An autonomous system (AS) is a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain, that presents a common and clearly defined ro ...

. While WHOIS essentially retrieves free text, RDAP delivers data in a standard, machine-readable JSON format. In order to accomplish this goal, the output of all operative WHOIS servers was analyzed, taking a census of the labels they used. RDAP designers, many of whom are members of

number A number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. More universally, individual numbers c ...

or name registries, strove to keep the protocol as simple as possible, since complexity was considered one of the reasons why previous attempts, such as CRISP, failed. RDAP is based on RESTful web services, so that error codes, user identification, authentication, and access control can be delivered through

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...

. The biggest delay in getting RDAP done turned out to be the ''bootstrap'', figuring out where the server is for each top level domain, IP range, or ASN range. IANA agreed to host the bootstrap information in suitable registries, and publish it at a well-known location URLs in JSON format. Those registries started empty and will be gradually populated as registrants of domains and address spaces provide RDAP server information to IANA. For number registries, ARIN set up a public RDAP service which also features a bootstrap URL, similar to what they do for WHOIS. For name registries, ICANN requires RDAP compliance since 2013.

Examples

An example of a RDAP client and server exchange: Client: GET /rdap/ip/203.0.113.0/24 HTTP/1.1 Host: rdap.example.com Accept: application/rdap+json rdap.example.com: HTTP/1.1 301 Moved Permanently Location: http://rdap-ip.example.com/rdap/ip/203.0.113.0/24 Content-Length: 0 Content-Type: application/rdap+json Client: GET /rdap/ip/203.0.113.0/24 HTTP/1.1 Host: rdap-ip.example.com Accept: application/rdap+json rdap-ip.example.com: HTTP/1.1 200 OK Content-Type: application/rdap+json Content-Length: 9001

Number resources

RDAP databases for assigned IP numbers are maintained by five

Regional Internet registries A regional Internet registry (RIR) is an organization that manages the allocation and registration of Internet number resources within a region of the world. Internet number resources include IP addresses and autonomous system (AS) numbers. ...

. ARIN maintains a bootstrap database. Thanks to the standard document format, tasks such as, for example, getting the abuse team address of a given IP number can be accomplished in a fully automated manner.

Name resources

RDAP databases for registered names are maintained after ICANN agreement. Name resources are much slower, as the number of registries under ICANN is huge. In addition, as the

GDPR The General Data Protection Regulation (GDPR) is a European Union regulation on data protection and privacy in the EU and the European Economic Area (EEA). The GDPR is an important component of EU privacy law and of human rights law, in parti ...

became enforceable, in May 2018, the problem of personal data divulged via WHOIS or RDAP slowed adoption further.

References

External links

IANA registry for RDAP services
* - A command line Registry Data Access Protocol (RDAP) client
rdap.org
- An end point for RDAP queries
RDAP JSON Values at IANA

RDAP page at APNIC

RDAP page at LACNIC
* * Internet protocols Internet Standards {{internet-stub