Introduction

Running a WHOIS lookup and suddenly getting hit with the error “TLD_NOT_SUPPORTED” can feel frustrating—especially when you’re just trying to grab some basic domain information. But don’t worry, this isn’t as complicated as it sounds.

In this guide, I’ll break down why this error happens and, more importantly, how you can fix it. Let’s dive in and get your WHOIS queries back on track. 🚀

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🔍 What Is a WHOIS Lookup, Anyway?

Before we jump into the solutions, let’s quickly cover the basics.

A WHOIS lookup helps you find details about a domain name—like who owns it, when it expires, and where it’s registered. It’s super handy for everything from buying domains to cybersecurity checks.

But sometimes, when you try to look up a domain, you might hit this error:

“Failed to perform lookup using WHOIS service: TLD_NOT_SUPPORTED.”

This simply means the WHOIS tool doesn’t recognize or support the Top-Level Domain (TLD) of the domain you’re searching for. TLDs are the endings of domain names—like .com, .net, .org, or newer ones like .ai or .tech.

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⚠️ Why Am I Seeing This Error?

There are a few reasons why this might be happening:

1. The domain extension (TLD) isn’t supported by the WHOIS tool you’re using.
2. Your WHOIS tool is outdated and doesn’t recognize newer TLDs.
3. The server for that specific TLD isn’t properly set up in your system.
4. Your network or firewall might be blocking the WHOIS service.
5. Certain TLDs have restrictions due to privacy laws like GDPR.

The good news? Each of these issues has a fix. Let’s go through them step by step.

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🔧 How to Fix the TLD_NOT_SUPPORTED Error

✅ 1. Double-Check the Domain Name

The simplest solution is often the most overlooked. A typo in the domain name could be causing the issue—especially if you’re dealing with unfamiliar TLDs.

Try this:

• Make sure the domain is spelled correctly.
• Verify that the TLD is valid. For example, .comm or .coom won’t work—only .com will.

Still stuck? Move on to the next step.

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🔄 2. Use an Updated WHOIS Tool

If your WHOIS tool is outdated, it might not recognize newer TLDs like .ai, .dev, or .app.

How to update your WHOIS client:

• On Linux (Debian-based):

  sudo apt update && sudo apt upgrade whois
  

• On Windows:
  • Use PowerShell to install a fresh WHOIS tool.
  • You can also try using third-party WHOIS applications like Sysinternals WHOIS.

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⚙️ 3. Set Up the Correct WHOIS Server

Not all WHOIS clients automatically know where to look for every TLD. You might need to manually point your tool to the right server.

Here’s how:

• Run a WHOIS command using the specific TLD server:

  whois -h whois.nic.[TLD] example.[TLD]
  

  🔗 Example: For an .ai domain, type:

  whois -h whois.nic.ai example.ai
  

• On Linux systems, you can also edit the configuration file (/etc/whois.conf) to add missing WHOIS servers permanently.

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🔒 4. Check Your Firewall and Network Settings

WHOIS lookups typically use port 43. If your network or firewall blocks this port, you won’t be able to run WHOIS queries.

Here’s what you can do:

• Try connecting through a VPN to bypass network restrictions.
• Check your firewall settings and ensure port 43 is open for outgoing traffic.

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🛡 5. Domain Registry Restrictions

Some domains hide WHOIS data due to privacy laws, like GDPR. In such cases, your lookup might not return any information, even if the TLD is supported.

Solution:

• Use registrar-specific WHOIS lookup tools. For example:
  • GoDaddy WHOIS
  • Namecheap WHOIS
• Contact the domain registrar directly for more information.

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📋 Quick Troubleshooting Cheat Sheet

Problem	Solution
Incorrect or unsupported TLD	Double-check the domain name and TLD
Outdated WHOIS tool	Update your WHOIS client
Missing WHOIS server configuration	Manually set the correct WHOIS server
Firewall blocking WHOIS requests	Use a VPN or unblock port 43
Privacy restrictions on domain	Use the registrar’s WHOIS tool

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🎨 Visual: How WHOIS Lookup Works

Here’s a simple illustration of the WHOIS lookup process and where things can go wrong:

🎨 (Image suggestion: A flow diagram showing a user sending a WHOIS request, the query traveling through the internet, hitting the WHOIS server, and either receiving the data or getting blocked due to TLD_NOT_SUPPORTED.)

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💡 Final Thoughts

The “TLD_NOT_SUPPORTED” error can be annoying, but it’s usually easy to fix once you know what’s causing it. Whether it’s updating your WHOIS tool, checking your domain’s spelling, or tweaking network settings, one of these solutions should have you sorted in no time.