Nguyễn Đình ThuyênAn open notebook
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← Networks
02 / Foundations · 2 min

Names need directions

DNS helps applications find information associated with a domain name, including IP addresses.

In 30 seconds

  1. A name lookup happens before many connections.
  2. Cached answers can reduce repeated lookups.
  3. A working name lookup does not prove the website itself is healthy.
Make it concrete

A directory may give the correct building address while its door is closed. Likewise, DNS and the service behind it are separate checks.

  1. 01Name
  2. 02Resolver
  3. 03Address
Concept diagram · simplified for learning
Check your understanding

If DNS returns an address, is the website guaranteed to load?

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Sources reviewed: 13.09.2026