---
title: "Naming: DNS and the Resolution Path"
description: "People use names and machines use addresses, so a distributed directory translates between them by walking a hierarchy from the root down. Caching with a time to live is what keeps it fast, and it is "
canonical: https://lightmysky.com/learn/computing/naming-dns-and-the-resolution-path-mt_omttmGkEgW
source: https://lightmysky.com/learn/computing/naming-dns-and-the-resolution-path-mt_omttmGkEgW.md
retrieved: 2026-09-12
---

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# Naming: DNS and the Resolution Path

People use names and machines use addresses, so a distributed directory translates between them by walking a hierarchy from the root down. Caching with a time to live is what keeps it fast, and it is also why a change takes a while to be seen everywhere.

Subject: Computing · Area: Networks & Security · Ages 19 to 20
Page: https://lightmysky.com/learn/computing/naming-dns-and-the-resolution-path-mt_omttmGkEgW

## Ready when they can

- Walk a name resolution from the root through to the answer
- Explain what the time to live decides and who honours it
- Say what a stale cached answer looks like from a user's side

## Lesson: How a name becomes an address

You type a short name and expect your favourite shop page to open. People use names and machines use addresses, so a distributed directory translates between them. A lookup walks a hierarchy from the root down to the server that knows the answer.

**Example.** For a name like shop.example.com, the root points to the com servers, those point to the example servers, and those give the address. Each level only knows the next step down.

Answers are cached to keep this fast. Each record carries a time to live, which says how long a resolver may reuse it. The resolver honours that lifetime before asking again.

After an address change, cached copies still point at the old server until their lifetime ends. From your side that looks like reaching the old site for hours.

**Recap.** Names walk down from the root, and caching decides how fast a change is seen.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [How a Web Page Reaches Your Screen](https://lightmysky.com/learn/computing/how-a-web-page-reaches-your-screen-mt_8JveAW2Mg7)
- [Congestion Control and Sharing a Link](https://lightmysky.com/learn/computing/congestion-control-and-sharing-a-link-mt_y5hPUrdKyq)

## Opens up

- [Routing: How a Path Is Learned](https://lightmysky.com/learn/computing/routing-how-a-path-is-learned-mt_gyqPDrV6Uo)