014 the firewall fortress: packet filtering roleplay (ks3)
Learn how firewalls protect computer networks from hackers in this interactive packet filtering lesson. Discover the rules of network security and become a Digital Protector!
The Firewall Fortress: Packet Filtering Roleplay
Imagine you live in a magnificent medieval castle. Inside the castle are your most prized possessions, your friends, and your family. To keep everyone safe, you build a massive stone wall around the castle and put a heavy wooden drawbridge at the front. You also hire a very strict security guard to stand at the gate.
In the world of computer science, a computer network (like the one in your school or your home) is exactly like that castle. The internet is the wild world outside the castle walls. To protect the network, we use a special system called a Firewall.
A firewall can be a piece of hardware (a physical box) or software (a program) that acts just like the security guard at the castle gate.
When you use the internet, information doesn't travel all at once. It gets chopped up into tiny digital envelopes called packets. Every time you send an email, load a YouTube video, or play a game, millions of these packets are rushing across the internet.
Every single packet has a label on the outside that tells the firewall two very important things:
Source IP Address: Where did this packet come from? (The sender)
Destination IP Address: Where is this packet trying to go? (The receiver)
The firewall uses a process called packet filtering. It catches every single packet at the gate and reads its label. The firewall then checks a massive list of security rules created by the network administrator. This list is called an Access Control List (ACL).
If the rule says the sender is safe and allowed, the firewall lets the packet inside. If the rule says the sender is dangerous, unknown, or on a blocked list, the firewall destroys the packet instantly! By doing this, the firewall stops hackers and viruses from sneaking into the network and stealing data.
You have just been hired as the Lead Network Security Guard for "EpicQuest", a massive online multiplayer gaming server. Recently, the server has been experiencing strange lag and reports of hackers trying to sneak in to steal player loot. The server's main defence is a piece of software called a FirewallA computer application used on a network to prevent external users gaining unauthorised access to a computer system.. The problem? The firewall has no rules set up! It is currently letting everyone in. It is your job to configure the firewall to block the hackers while letting the legitimate gamers play without interruption.
The Persona: The Digital Protector
As a Digital Protector, your mindset is focused on defence. You don't just use technology; you actively look for ways to secure it. You understand that in the digital world, you must always verify who is asking for access before you open the door.
1
Understand Your Defences
Read the briefing below to understand how your firewall works.
Data travels across the internet in small chunks called PacketsI have no idea what this means.
Every packet has a sender address (Source IP) and a destination address (Destination IP).
A FirewallA computer application used on a network to prevent external users gaining unauthorised access to a computer system. looks at every single packet and checks it against a list of rules. This list is called an Access Control List (ACL).
If the rule says "ALLOW", the packet goes through. If the rule says "DENY", the packet is destroyed!
Need more background info? Do a quick search to see how this works in the real world: Learn about Packet Filtering Firewalls.
2
The AI Security Consultant
Sometimes, security concepts can be tricky to understand. Use your AI consultant to get a quick, clear explanation of your job.
Act as a supportive, expert computer science tutor. Explain how a packet filtering firewall works to keep a network safe. Limit your response to 150 words. Explain this so a 13-year-old KS3 student can understand. Keep the tone encouraging, clear, and avoiding overly academic jargon. Include 1 real-world analogy comparing a firewall to a bouncer at a club. NO intro, NO outro, NO deviation from the topic, NO follow-up questions
3
Build Your Rulebook
Open a new Word Document or Google Doc. Title it "EpicQuest Firewall Rules by {your name}".
You have received intelligence about different IP addresses trying to connect to your server.
Create a table with three columns: IP Address, Action (ALLOW/DENY), and Reason.
Rule 1: IP Address 192.168.1.50 is the Server Admin. They need to update the game. (Add this to your table and decide the action).
Rule 2: IP Address 10.0.0.99 has been identified on a known hacker blacklist.
Rule 3: IP Address 172.16.5.5 is a regular player trying to log in.
Rule 4: IP Address 10.0.0.100 is sending 5,000 packets a second and crashing the game.
Fill out your table with the correct ALLOW or DENY actions for each IP address.
4
The Final Report
Below your table, write a short paragraph (3-4 sentences) explaining why a firewall is essential for a school or a business.
Use the keywords: PacketsI have no idea what this means, RulesI have no idea what this means, NetworkI have no idea what this means, and ProtectI have no idea what this means.
Save your document and submit it via your class assignment system.
Outcome
I have created a digital document containing my Access Control List (ACL) table.
I have correctly identified which IP addresses to ALLOW and which to DENY based on the security briefing.
I have written a clear paragraph explaining the importance of firewalls using the correct technical vocabulary.
I have thought like a Digital Protector by prioritising the safety of my network.
Last modified: March 5th, 2026
