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Mohd Asif Ansari
Mohd Asif Ansari

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DNS Record Types Explained

#webdev #beginners #networking #dns

You type "google.com" in your browser and it loads. But how does your computer know where Google actually is?

That's DNS (Domain Name System) - the internet's phonebook. It has different types of records for different purposes.

Let me break down the main ones.

What Are DNS Records?

DNS records answer one question: "Where should this request go?"

Different record types give different answers:

  • "Here's the IP address" (A Record)
  • "Go ask that other domain" (CNAME Record)
  • "Send email here" (MX Record)
  • "These servers control this domain" (NS Record)

1. A Record: The Basic Address

What it does: Maps a domain name to an IP address.

Example:

example.com  →  192.168.1.1
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When someone types "example.com", DNS says "go to 192.168.1.1"

Real use: You point your domain to your server's IP address.

Key point: A records work with IPv4 addresses (like 192.168.1.1).

2. CNAME Record: The Alias

What it does: Points one domain name to another domain name.

Example:

www.example.com  →  example.com
blog.example.com  →  example.com
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Real use:

  • Make www.yoursite.com and yoursite.com go to the same place
  • Use blog.yoursite.com but host on Medium
  • Route traffic through a CDN

Key point: CNAME redirects to another domain, which then has an A record pointing to the IP.

A Record vs CNAME

A Record: Points directly to an IP

example.com  →  192.168.1.1
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CNAME: Points to another domain

www.example.com  →  example.com  →  192.168.1.1
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Important: You can't use CNAME for your root domain (example.com). Only subdomains can be CNAMEs.

3. MX Record: Email Routing

What it does: Tells email servers where to send emails for your domain.

Example:

example.com  →  mail.example.com  (priority: 10)
example.com  →  backup-mail.example.com  (priority: 20)
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How it works:

  1. Someone emails you@example.com
  2. Their email server checks MX records
  3. Email goes to the server with lowest priority number

Real use: Point your domain's email to Gmail or Outlook servers.

Key point: Lower priority number = tried first. If it fails, tries the next one.

4. NS Record: Who's in Control

What it does: Says which DNS servers control your domain.

Example:

example.com  →  ns1.cloudflare.com
example.com  →  ns2.cloudflare.com
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Real use: You buy a domain from GoDaddy but use Cloudflare for DNS. You change NS records to Cloudflare's servers.

Key point: NS records determine who manages all your other DNS records.

NS vs MX: The Difference

NS Record: Which servers control ALL DNS for this domain

MX Record: Which servers handle EMAIL only

How They Work Together

Real example for company.com:

A Record:
company.com  →  93.184.216.34

CNAME Records:
www.company.com  →  company.com
blog.company.com  →  company.com

MX Records:
company.com  →  smtp.google.com  (priority: 10)

NS Records:
company.com  →  ns1.cloudflare.com
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What this means:

  • Main site is at that IP
  • www and blog point to the same server
  • Emails go to Google
  • Cloudflare manages the DNS

Complete Flow for www.company.com

  1. Browser asks: "What's www.company.com?"
  2. DNS checks NS records: "Ask Cloudflare"
  3. Cloudflare checks CNAME: "It's an alias for company.com"
  4. Cloudflare checks A record: "That's 93.184.216.34"
  5. Browser connects to that IP

Happens in milliseconds!

Common Setups

Simple Website:

yoursite.com      →  192.168.1.1  (A)
www.yoursite.com  →  yoursite.com  (CNAME)
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Website + Email:

yoursite.com      →  192.168.1.1  (A)
www.yoursite.com  →  yoursite.com  (CNAME)
yoursite.com      →  mail.google.com  (MX)
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Using CDN:

yoursite.com      →  192.168.1.1  (A)
www.yoursite.com  →  yoursite.cdn.com  (CNAME)
yoursite.com      →  ns1.cloudflare.com  (NS)
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Why Developers Need This

You'll use DNS records for:

  • Deploying sites: Point domain to server IP
  • Subdomains: Create api.yoursite.com or dev.yoursite.com
  • Email setup: Configure business email
  • CDNs: Route through Cloudflare or AWS
  • Debugging: Check DNS when sites don't load

Interview tip: Know A vs CNAME and what MX/NS records do.

Quick Summary

  • A Record: Domain → IP address
  • CNAME Record: Domain → Another domain (alias)
  • MX Record: Where emails go (with priority)
  • NS Record: Which servers control DNS

Remember:

  • A points to IPs, CNAME points to domains
  • MX is for email, NS is for DNS control
  • Lower MX priority number = higher priority
  • Can't use CNAME on root domain

Understanding DNS helps you deploy sites, fix issues, and ace interviews.

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