DNS Explained – How Domains Actually Work (And How to Configure Them)

Every time you visit a website, something critical happens behind the scenes:

👉 A domain name is translated into an IP address.

This process is called DNS (Domain Name System) — and understanding it is essential for:

• Hosting servers
• Managing domains
• Running self-hosted apps

🔹 What is DNS?

DNS is like the phonebook of the internet.

Instead of remembering:

142.250.74.78

You use:

google.com

DNS resolves the domain → IP.

🔹 How DNS Works (Step-by-Step)

1. You type a domain (e.g. example.com)
2. Request goes to a DNS resolver (ISP or public DNS)
3. Resolver queries:
   • Root servers
   • TLD servers (.com)
   • Authoritative server
4. IP is returned → browser connects

🔹 Common DNS Record Types

A Record

Points domain → IPv4

example.com → 192.168.1.1

AAAA Record

Points domain → IPv6

example.com → 2001:db8::1

CNAME Record

Alias for another domain

www.example.com → example.com

MX Record

Mail servers

example.com → mail.example.com

TXT Record

Used for:

• Verification
• SPF, DKIM (email security)

🔹 Real Example (Cloudflare Setup)

Using Cloudflare DNS:

Type	Name	Value
A	example.com	your-server-ip
CNAME	www	example.com
A	app	your-server-ip

🔹 DNS Propagation

After changing DNS:

• It can take seconds → 24 hours
• Depends on TTL (Time To Live)

🔹 Check DNS Records

dig example.com

or

nslookup example.com

🔹 Pro Tips (Advanced)

• Use low TTL while testing (300 seconds)
• Use separate subdomains for services:
  • app.domain.com
  • api.domain.com
• Never expose internal services directly

🔹 Common Mistakes

❌ Wrong IP address
❌ Missing CNAME for www
❌ Mixing proxy + direct DNS incorrectly

🔹 Conclusion

Understanding DNS gives you:

• Full control over your infrastructure
• Cleaner architecture
• Better security

👉 It’s the foundation of everything in networking.