About RDAP.nu

What is RDAP?

RDAP (Registration Data Access Protocol) is the modern, standardized replacement for the legacy WHOIS protocol. Developed by the IETF, RDAP provides structured, machine-readable registration data for domains, IP addresses, and autonomous system numbers (ASNs).

Why RDAP over WHOIS?

RDAP offers structured JSON responses instead of inconsistent plain text, standardization across all registries worldwide, proper Unicode and language support, HTTPS transport with authentication, and extensibility for custom fields.:

• Structured data: JSON responses instead of inconsistent plain text
• Standardized: Same format across all registries worldwide
• Internationalization: Proper Unicode and language support
• Secure: HTTPS transport with authentication support
• Extensible: Registries can add custom fields while maintaining compatibility
• Differentiated access: Support for varying access levels based on user authentication

What does this tool do?

RDAP.nu queries both RDAP and traditional WHOIS sources, normalizes the data into a consistent format, and lets you compare the results side by side:

• See what data is available from each protocol
• Verify registration information across sources
• Understand the transition from WHOIS to RDAP
• Access registration data in a clean, readable format

What types of lookups are supported?

RDAP.nu supports domain lookups (.com, .net, .org, and most TLDs), IPv4 and IPv6 address lookups from all five Regional Internet Registries, and Autonomous System Number (ASN) lookups from ARIN, RIPE, APNIC, LACNIC, and AFRINIC.:

• Domains: .com, .net, .org, and most TLDs with RDAP support
• IP Addresses: IPv4 and IPv6 addresses from all RIRs
• ASNs: Autonomous System Numbers from ARIN, RIPE, APNIC, LACNIC, and AFRINIC

Data Sources

This tool queries authoritative sources based on the IANA bootstrap files, which map resources to their responsible registries. For WHOIS, we use the standard WHOIS protocol to query each registry's WHOIS server directly.

Regional Internet Registries (RIRs):

• ARIN - American Registry for Internet Numbers
• RIPE NCC - Europe, Middle East, Central Asia
• APNIC - Asia-Pacific region
• LACNIC - Latin America and Caribbean
• AFRINIC - Africa

How to Read RDAP Results

RDAP results use standardized field names. Here are the most common ones:

• Status codes: active means the resource is in use. client transfer prohibited and similar "prohibited" statuses indicate registrar-level locks that protect against unauthorized changes.
• Handle: The unique identifier assigned by the registry (e.g., AS13335 for an ASN, or a network handle like NET-8-8-8-0-1).
• DNSSEC: Indicates whether the domain has DNS Security Extensions enabled, which protects against DNS spoofing.
• Dates: created, updated, and expires show the resource lifecycle. Expiry dates are most relevant for domain lookups.
• Contacts: abuse, admin, and tech contacts are typically email addresses for reporting issues or technical coordination.

Try looking up example.com, 8.8.8.8, or AS15169 to see these fields in action.

RDAP Standards

RDAP is defined by several IETF RFCs:

• RFC 9083: JSON Responses for the Registration Data Access Protocol — defines the data model
• RFC 9082: Registration Data Access Protocol Query Format — defines URL patterns for queries
• RFC 7480: HTTP Usage in RDAP — specifies transport and content negotiation
• RFC 7484: Finding the Authoritative RDAP Service — describes the IANA bootstrap mechanism