038: dns: the phonebook of the internet (ks4)
Unlock the secrets of the internet's phonebook in this KS4 lesson on the Domain Name System (DNS).
The Internet's Invisible Directory
The Scenario
You are working as a Junior Network Engineer for a web hosting company. A client has reported that their website, www.tech-example.com, is loading slowly or not at all for some customers. Your manager suspects a DNS configuration issue. To troubleshoot this, you need to verify how the domain name is being translated (resolved) into an IP address and explain the process to the client.
The System Integrator
As a System IntegratorI have no idea what this means, you understand that hardware, software, and networks must work together seamlessly. You focus on connection and communication. You don't just see a webpage; you see the invisible handshake between the client's browser and the web server. Your goal is to ensure that these systems can talk to each other efficiently.
You are working as a Junior Network Engineer for a web hosting company. A client has reported that their website, www.tech-example.com, is loading slowly or not at all for some customers. Your manager suspects a DNS configuration issue. To troubleshoot this, you need to verify how the domain name is being translated (resolved) into an IP address and explain the process to the client.
As a System IntegratorI have no idea what this means, you understand that hardware, software, and networks must work together seamlessly. You focus on connection and communication. You don't just see a webpage; you see the invisible handshake between the client's browser and the web server. Your goal is to ensure that these systems can talk to each other efficiently.
1
Deconstruct the URL
Create a new document titled DNS Investigation.
A URL (Uniform Resource Locator) is a specific address. Look at this example
https://www.bbc.co.uk/news/technology
In your document, explain what each part of that address represents:
Protocol: (e.g., https)
Subdomain: (e.g., www)
Domain Name: (e.g., bbc)
Top-Level Domain (TLD): (e.g., .co.uk)
Path: (e.g., /news/technology)
2
The DNS Lookup Journey
When a user types a URL, a complex process called DNS Resolution occurs.
Create a numbered list or a diagram explaining these four key steps in order:
1. The Browser Cache: What happens first?
2. The Recursive Resolver: Who does the computer ask for help (often your ISP)?
3. The Root Nameserver & TLD Nameserver: How does the system find the right ending (like .com or .uk)?
4. The Authoritative Nameserver: Who holds the final answer (the IP address)?
3
Perform a DNS Lookup
You need to find the "phone number" (IP Address) for specific websites.
Open Command Prompt (Windows key + type "cmd") OR use this online tool: DNS Checker.
Run a lookup for these three sites. If using CMD, type
nslookup website.comgoogle.com
bbc.co.uk
roblox.com
Take a screenshot of your results.
Analysis: Identify the IP Address for each site. Note that big sites often have multiple IP addresses!
4
Report to the Client
Write a short professional paragraph (approx 100 words) summarising your findings.
Explain why computers use IP addresses (like 142.250.187.206) instead of words.
Explain why DNS is essential for their customers (mention usability and memory).
Outcome
Break down of URL structure identifying Protocol, Domain, and TLD.
Explanation/Diagram of the DNS resolution steps.
Screenshots of practical DNS lookups showing IP addresses.
Summary paragraph explaining the purpose of DNS.
Last modified: December 15th, 2025
