How DNS Resolution Works

You type google.com. Your browser has no idea where that is.

So it asks DNS. And DNS doesn't just know the answer — it finds it, layer by layer, in milliseconds.

Let's trace that journey using dig.

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What is dig?

dig (Domain Information Groper) is a DNS diagnostic tool. It lets you query DNS servers directly and see exactly what's happening under the hood.

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Layer 1: Root Name Servers

Everything starts at the root. There are 13 root server clusters worldwide.

dig . NS

Output:

.                       518400  IN  NS  a.root-servers.net.
.                       518400  IN  NS  b.root-servers.net.
.                       518400  IN  NS  m.root-servers.net.

These servers don't know where google.com is. But they know who manages .com.

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Layer 2: TLD Name Servers

Next, we ask: "Who handles .com domains?"

dig com NS

Output:

com.                    172800  IN  NS  a.gtld-servers.net.
com.                    172800  IN  NS  b.gtld-servers.net.
com.                    172800  IN  NS  m.gtld-servers.net.

These are the TLD (Top-Level Domain) servers. They manage every .com domain — but still don't know Google's IP.

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Layer 3: Authoritative Name Servers

Now we ask: "Who's authoritative for google.com?"

dig google.com NS

Output:

google.com.             21600   IN  NS  ns1.google.com.
google.com.             21600   IN  NS  ns2.google.com.
google.com.             21600   IN  NS  ns3.google.com.
google.com.             21600   IN  NS  ns4.google.com.

These are Google's own nameservers. They have the final answer.

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The Full Resolution

Finally, get the IP address:

dig google.com

Output:

google.com.             300     IN  A   142.250.193.206

That's it. Your browser now knows where to go.

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The Complete Flow

Browser → Recursive Resolver → Root NS → TLD NS → Authoritative NS → IP

Every single web request follows this path. Caching makes it faster, but the hierarchy never changes.

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Quick Reference

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DNS isn't magic. It's a layered lookup — root to TLD to authoritative. Now you can trace it yourself.

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