When you need to investigate problems related to domains, IP addresses, or DNS configurations, obtaining accurate and up-to-date information is essential. The RDAP (Registration Data Access Protocol) has become the modern standard for querying registration data, gradually replacing the traditional WHOIS.

If you work from Windows or Mac and need to access detailed information about domains, IP ranges, or autonomous system numbers, RDAP provides structured responses in JSON format that are easier to process and analyze than WHOIS plain text responses.

Situations where RDAP is useful

It's common to face situations where you need to quickly verify domain or IP address information:

• The client reports DNS problems and you need to verify the configured nameservers
• You need to identify the owner of an IP address that is generating unusual traffic
• You need to confirm the registration and expiration dates of a domain
• You must investigate the configuration of a domain that is not resolving correctly
• You want to verify the status of a domain before proceeding with a migration

Environment preparation

To start using RDAP, the most direct method is to install OpenRDAP, which is the most reliable and widely used tool on both platforms.

Installation on Windows

The simplest process is to download the executable directly:

1. Visit the releases page on GitHub: https://github.com/openrdap/rdap/releases
2. Download the rdap-windows-amd64.exe file
3. Move the file to an accessible location, such as C:\Windows\System32\ and rename it to rdap.exe
4. Open PowerShell or Command Prompt and verify the installation by running:rdap --version

If you prefer to use a package manager, you can also install OpenRDAP with Chocolatey: choco install openrdap

Installation on Mac

On Mac, installation is even more straightforward using Homebrew:brew install openrdap

Verify the installation:rdap --version

Basic domain queries

Once installed, you can start with simple queries on either platform. To verify domain information: rdap example.com

This command will show you basic domain information in readable text format. If you prefer to get the response in JSON for more detailed analysis:rdap -j example.com

For domains with specific extensions, you can direct the query directly to the appropriate server:rdap -s https://rdap.verisign.com/com/v1/ example.com

IP address and network range verification

When you need to identify the owner of an IP address or verify network information:rdap 192.168.1.1

To get more detailed information in JSON format:rdap -j 8.8.8.8

This query will provide you with details about the network range, owning organization, country of registration, and other relevant information.

Autonomous System Number (ASN) queries

If you need information about a specific ASN:rdap AS15169

This is particularly useful when investigating the origin of network traffic or when you need to identify the connectivity provider.

Advanced searches

RDAP also allows pattern searches to find multiple results:rdap -t domain-search "example*"

To search for specific nameservers:rdap -t nameserver-search "ns1*"

Script automation

PowerShell on Windows

PowerShell allows you to process RDAP JSON responses more efficiently. For example, to extract only the nameservers from a domain:$result = rdap -j example.com | ConvertFrom-Json
$result.nameServers | Select-Object ldhName

To verify the status of multiple domains:

$domains = @("example1.com", "example2.com", "example3.com")
$domains | ForEach-Object {
$info = rdap -j $_ | ConvertFrom-Json
Write-Host "$_ - Status: $($info.status -join ', ')"
}

Terminal on Mac

On Mac, you can use native tools to process JSON. To extract nameservers using jq install with brew install jq

rdap -j example.com | jq '.nameServers[].ldhName'

To verify multiple domains in bash:

for domain in example1.com example2.com example3.com; do
echo "Checking: $domain"
rdap -j $domain | jq -r '.status[]'
done

You can also create a useful function in your .zshrc or .bash_profile

rdap_info() {
echo "🌐 RDAP Info for: $1"
rdap -j $1 | jq -r '
"🏷️ Name: " + .ldhName,
"📅 Registration: " + (.events[] | select(.eventAction == "registration") | .eventDate),
"🖥️ NS: " + .nameServers[].ldhName
'
}

Optimization and best practices

For more efficient use of RDAP, consider these tips regardless of your platform:

Specify the server when possible: If you know the domain extension, directing the query to the specific server is faster:

• For .com/.net: rdap -s https://rdap.verisign.com/com/v1/ domain.com
• For .org: rdap -s https://rdap.publicinterestregistry.net/rdap/ domain.org

Use appropriate timeouts: For slow networks or servers that respond slowly:

rdap -T 60 slow-domain.com

Save responses for later analysis: When you need to process multiple queries:

On Windows:

rdap -j example.com > domain_info.json

On Mac:

rdap -j example.com > domain_info.json

Combine verbose with JSON for debugging: If a query doesn't work as expected:

rdap -v -j example.com

Common use cases in hosting

In the context of hosting and domain administration, RDAP is especially useful for:

DNS configuration verification: Before migrating a website, you can confirm the current nameservers and compare them with your target configuration.

Connectivity problem investigation: When a client reports access problems, you can quickly verify the source IP address information.

Domain auditing: For clients with multiple domains, you can automate the verification of expiration dates and registration statuses.

Traffic analysis: Quickly identify the geographical and organizational origin of IP addresses in server logs.

Workflow integration

Windows with PowerShell

You can create scripts that integrate with other administration tools:

# Verify nameservers before a migration
$domain = "example.com"
$currentNS = (rdap -j $domain | ConvertFrom-Json).nameServers.ldhName
Write-Host "Current NS: $($currentNS -join ', ')"

Mac with Terminal

Create useful aliases in your shell profile:

alias rdapj='rdap -j'
alias rdap-ns='rdap -j | jq ".nameServers[].ldhName"'
alias rdap-status='rdap -j | jq ".status"'

The adoption of RDAP as a WHOIS replacement means you will have access to more structured and reliable information. Unlike WHOIS, which can vary in format between different registries, RDAP provides consistent responses that facilitate automation and programmatic analysis.

To maintain an efficient workflow, consider creating custom scripts that combine RDAP queries with other administration tools. The structured information provided by RDAP integrates perfectly with monitoring tools and infrastructure management systems, regardless of whether you work from Windows or Mac.