What Is DNS? (Domain Name System Explained Simply)

Have you ever typed a website like google.com into your browser and wondered how your computer knows where to go?

The answer is DNS.

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What Does DNS Stand For?

DNS stands for Domain Name System.

It translates human-friendly domain names into IP addresses that computers use to communicate.

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Why Do We Need DNS?

Computers communicate using IP addresses like:

142.250.72.14

But humans prefer names like:

google.com

DNS connects the two.

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How Does DNS Work? (Step-by-Step)

1. You type google.com into your browser.
2. Your computer asks a DNS server: “What is the IP for google.com?”
3. The DNS server responds with the correct IP address.
4. Your browser connects to that IP.

This entire process usually happens in milliseconds.

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What Is a DNS Server?

A DNS server is a system that stores and provides IP address mappings.

Common public DNS servers include:

• 8.8.8.8 (Google DNS)
• 1.1.1.1 (Cloudflare DNS)

Most home routers automatically assign a DNS server via DHCP.

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Common DNS Problems (A+ Exam Clues)

If DNS fails, you might notice:

• You can ping an IP address but not a website name.
• Websites won’t load, but internet connection appears active.
• “DNS server not responding” errors.

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How to Troubleshoot DNS Issues

1. Run:

ipconfig /flushdns

2. Try a different DNS server (like 8.8.8.8).
3. Restart your router.
4. Check DHCP settings.

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DNS and DHCP (How They Work Together)

DHCP assigns IP addresses.

DNS translates domain names.

Without DHCP, your device may not get an IP.

Without DNS, your device can’t resolve website names.

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Final Summary

• DNS stands for Domain Name System
• It translates domain names into IP addresses
• DNS servers store these mappings
• If DNS fails, websites won’t resolve
• DNS issues are common troubleshooting scenarios on CompTIA A+