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Understanding RDAP

Everything you need to know about the Registration Data Access Protocol

What is RDAP?

Registration Data Access Protocol (RDAP) is a modern protocol designed to replace WHOIS for querying registration data of Internet resources, including domain names, IP addresses, and autonomous system numbers.

Key Features of RDAP

  • Standardized JSON responses for better machine readability
  • Built-in support for internationalized domain names
  • Structured error responses
  • Authentication and access control mechanisms
  • RESTful API design

How RDAP Works

RDAP operates over HTTPS, making it more secure and reliable than the traditional WHOIS protocol. Here's how it works:

  1. Client sends an HTTPS request to an RDAP server
  2. Server authenticates the request (if required)
  3. Server processes the query and retrieves relevant data
  4. Response is returned in JSON format

Advantages Over WHOIS

Structured Data

Unlike WHOIS's free-text format, RDAP returns data in structured JSON, making it easier to parse and process programmatically.

Internationalization

RDAP fully supports Unicode and internationalized domain names, addressing one of WHOIS's major limitations.

Security

Built-in support for authentication and authorization allows for tiered access to registration data, helping with privacy compliance.

Implementation Status

RDAP is now widely supported by regional internet registries (RIRs) and many domain registries. ICANN requires all gTLD registries and registrars to provide RDAP services, marking a significant shift away from WHOIS.

Future of RDAP

As RDAP adoption continues to grow, we can expect:

  • Enhanced privacy features and granular access controls
  • Better integration with modern web services
  • Extended query capabilities
  • Standardized implementation across all registries

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