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Introduction to RDAP

RDAP (Registration Data Access Protocol) is the modern successor to WHOIS, providing structured access to domain name, IP address, and autonomous system registration information. This Rust implementation offers both a powerful CLI tool and a flexible library for programmatic access.

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What is RDAP?

RDAP is a standardized protocol (RFC 7480-7484) that provides:
  • Structured JSON responses instead of unformatted text
  • RESTful HTTP API with consistent query patterns
  • Internationalization support for non-ASCII domain names
  • Authentication and access control capabilities
  • Standardized data models across all registries
RDAP replaces the traditional WHOIS protocol with a modern, RESTful approach that’s easier to parse and more consistent across different registries.

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What This Tool Does

This RDAP client provides elegant access to registration data for:

Domains

Query registration details for any domain name, including registrant information, nameservers, and DNSSEC status

TLDs

Look up top-level domain information directly from IANA, including administrative and technical contacts

IP Addresses

Query both IPv4 and IPv6 addresses with CIDR support to find allocation details and abuse contacts

AS Numbers

Look up autonomous system information including name, type, and routing contacts

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Key Features

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Modern & Fast

  • Asynchronous I/O powered by Tokio for high performance
  • Efficient HTTP client with connection pooling via reqwest
  • Fast JSON parsing using Serde for type-safe deserialization
  • Small binary size (~4MB stripped)

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Beautiful Output

$ rdap google.com

Abuse contact for `google.com` is `abusecomplaints@markmonitor.com`

Query from https://rdap.verisign.com/com/v1/domain/google.com

Domain Name: GOOGLE.COM
Handle: 2138514_DOMAIN_COM-VRSN
Status: client delete prohibited
Status: client transfer prohibited
Nameserver: NS1.GOOGLE.COM
Registration: 1997-09-15T04:00:00Z
Expiration: 2028-09-14T04:00:00Z
The tool automatically displays abuse contacts at the top of results for domains, IPs, and AS numbers, making it easy to report issues.

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Full RDAP Support

  • Domain name queries with multi-layer support (registry + registrar)
  • TLD queries for top-level domain information
  • IPv4 and IPv6 address queries
  • CIDR network range queries (e.g., 8.8.8.0/24)
  • AS number queries (with or without “AS” prefix)
  • Entity (contact) queries
  • Nameserver queries
  • Search queries for domains, entities, and nameservers

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Smart Features

1

Auto-Detection

Query type is automatically detected - just type rdap 8.8.8.8 and the tool knows it’s an IP address
2

Bootstrap Discovery

Automatically finds the authoritative RDAP server using IANA’s bootstrap service
3

Multi-Layer Queries

For domains, automatically follows referrals from registry to registrar for complete information
4

Smart Normalization

IP shorthand like 1.1 is automatically expanded to 1.0.0.1

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Configuration & Customization

  • Zero-config usage with built-in defaults embedded in the binary
  • TLD overrides for ccTLDs not in IANA bootstrap
  • Custom RDAP servers via command-line flag
  • Local override files (*.local.json) that survive updates
  • Update command to fetch latest configs from GitHub
# Update configuration files from GitHub
rdap --update
Configuration files are loaded with priority: local overrides → user config → system config → built-in defaults

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Use Cases

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Network Operations

  • Investigate network abuse by quickly finding abuse contacts
  • Verify IP allocation and ownership
  • Check AS number routing information

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Domain Management

  • Monitor domain expiration dates
  • Verify nameserver configurations
  • Check DNSSEC status
  • Audit registrar information

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Security Research

  • Investigate suspicious domains or IPs
  • Track infrastructure ownership
  • Correlate registration data across resources

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Automation & Integration

  • Use as a Rust library in your applications
  • Parse JSON output for pipeline integration
  • Build custom tools on top of the RDAP API

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Architecture Overview

The project is structured as both a library (rdap crate) and a CLI tool: 
src/
├── lib.rs           # Library entry point, public API
├── main.rs          # CLI entry point with clap
├── client.rs        # RdapClient - main query orchestration
├── request.rs       # RdapRequest and QueryType
├── bootstrap.rs     # IANA bootstrap service discovery
├── config.rs        # Configuration management
├── display.rs       # Colored terminal output
├── cache.rs         # Bootstrap file caching
├── ip.rs            # IP normalization and CIDR handling
└── models/          # RDAP data models
    ├── domain.rs
    ├── entity.rs
    ├── autnum.rs
    ├── ip_network.rs
    └── ...

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RFC Compliance

This implementation follows official RDAP specifications:

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Next Steps

Installation

Install the RDAP client using apt, brew, cargo, or from source

Quickstart

Get started with your first RDAP query in under 2 minutes

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