Networking - DNS

What is DNS?

DNS (Domain Name System) is like the phonebook of the internet.

When you type a website name like www.google.com into your browser, DNS helps translate that name into a number (called an IP address) that computers use to find each other.

Real-Life Analogy

Just like you use a contact name like “Mom” to call someone instead of remembering their phone number,
you use “www.google.com” instead of “142.250.190.4”.

DNS does the job of finding the correct number (IP address) behind the name.

How DNS Works (Step-by-Step)

1. You type a website address in your browser: www.example.com

2. Your computer asks the DNS server:
   “What is the IP address of www.example.com?”

3. DNS server replies with the IP address:
   For example, 93.184.216.34

4. Your browser uses that IP to connect to the website’s server.

5. The website opens!

Key Terms to Know

• Domain Name: A human-friendly website name (like www.facebook.com)

• IP Address: A unique number assigned to each device on the internet

• DNS Server: A computer that stores and looks up domain names and their IPs

Why DNS is Important

• It makes the internet easy to use (you don’t have to remember IP addresses).

• It helps connect users to websites quickly and correctly.

• It keeps the internet organized and scalable.

 Types of DNS Servers

1. DNS Resolver (Local): First point of contact for your device.

2. Root Server: Knows where to find top-level domains (.com, .org, .net).

3. TLD Server: Knows where to find specific domain types like .com.

4. Authoritative DNS Server: Holds the actual IP address of the website.

Example

• You type: www.openai.com

• DNS returns: 104.18.30.162

• Your computer connects to that number to load OpenAI’s website.