Firewalls

Habari Mwanafunzi! Meet the Digital Askari: Your Computer's Firewall!

Hello there, future tech expert! Today, we are going to talk about something very important in the world of computers, something that acts like a security guard, or as we call them here in Kenya, an Askari. Imagine your school gate. The askari stands there, right? He checks who is coming in and who is going out. He lets students and teachers in but stops strangers who might cause trouble. Sawa?

In the digital world, your computer or phone also has an askari. This digital askari is called a Firewall, and its job is to protect you from dangers on the internet. Let’s dive in and learn how it keeps you safe!

Image Suggestion: A friendly, smiling Kenyan security guard (askari) in uniform standing next to a large, glowing digital shield. The shield is protecting a group of happy students using laptops. In the background, cartoony computer viruses and hacker symbols are bouncing off the shield. The style should be colourful and illustrative.

What Exactly is a Firewall?

A firewall is a security barrier that sits between your computer (or your school's whole network) and the vast world of the Internet. The internet is like a huge, busy market in town – full of amazing things but also some pickpockets and tricksters! The firewall decides what information (we call this traffic) is safe to let in and what should be blocked.

Think of it as a wall with a very smart gate.

        Your Computer/Phone              The Internet (A big, busy world!)
      +-----------------+          +--------------------------------------+
      |  Your Safe      |          |                                      |
      |  Information    | <------> |  Websites, Games, Videos, Emails     |
      |  (Trusted)      |          |  ...and also Hackers & Viruses!      |
      +-----------------+          |  (Untrusted)                         |
             ^                     +--------------------------------------+
             |
             |
     +-----------------+
     |   THE FIREWALL  |
     |   (Your Digital |
     |      Askari)    |
     +-------|---------+
             |
        Checks all traffic!

How Does It Know What to Block? The "Rule Book"

A good askari has a list of rules. For example: "Rule 1: Only students in uniform are allowed in during school hours." A firewall also has a list of rules! This is called its policy. It checks every piece of data trying to enter or leave your computer against this rule book.

• It checks where the traffic is coming from.
• It checks where the traffic is going.
• It checks what 'port' or 'door' it's trying to use. (Think of this like a specific gate for different things - one for email, one for websites).

Real-World Scenario: Imagine you are using the M-Pesa app on your parent's phone to buy something. The firewall on the phone has a rule that says, "Traffic from the official M-Pesa app trying to talk to Safaricom's servers is SAFE. ALLOW it." But then, a strange pop-up ad tries to connect to a website you've never heard of. The firewall checks its rules and says, "Hmm, this looks suspicious and isn't on my list of safe places. BLOCK it!"

Here’s what a simple set of firewall rules might look like in plain English:

    RULE 1: IF traffic is from "WhatsApp" ==> THEN ALLOW
    RULE 2: IF traffic is for "YouTube.com" ==> THEN ALLOW
    RULE 3: IF traffic is from "UnknownHacker.net" ==> THEN BLOCK & ALERT!
    RULE 4: IF traffic is trying to use "Port 25" (for email) but is NOT an email app ==> THEN BLOCK

Software vs. Hardware Firewalls

There are two main types of these digital askaris, and they work in slightly different ways.

• Software Firewall: This is a program installed on your single computer. It’s like having a personal bodyguard just for you! Windows and macOS have them built-in. It protects only the device it is on.
• Hardware Firewall: This is a physical device, often part of your Wi-Fi router (that box that gives you internet). It’s like the main askari at the gate of a whole housing estate or school, protecting every single computer on the network.

Image Suggestion: A split-screen image. On the left, a single laptop with a glowing shield icon on its screen, labeled "Software Firewall." On the right, a physical Wi-Fi router box connected to a wall, with a larger glowing shield protecting three different computers and a phone connected to it, labeled "Hardware Firewall."

Let's Do Some Quick Maths!

Firewalls handle a LOT of traffic. Imagine your school's firewall is working for one hour. In that time, 20,000 data packets try to enter the network from the internet. The firewall's rules find that 3,000 of these packets are from blocked websites or are trying to do something suspicious.

What percentage of the traffic was blocked? Let's calculate!

    Step 1: Find the formula.
    Percentage Blocked = (Blocked Packets / Total Packets) * 100

    Step 2: Put in our numbers.
    Percentage Blocked = (3,000 / 20,000) * 100

    Step 3: Do the division.
    3,000 / 20,000 = 0.15

    Step 4: Multiply by 100 to get the percentage.
    0.15 * 100 = 15%

    Answer: The firewall successfully blocked 15% of all incoming traffic, keeping the network safe!

Why Is This So Important?

Without a firewall, using the internet would be like leaving the front door of your house wide open in a busy town! Here’s why they are crucial:

• They Stop Hackers: They block unauthorised users from accessing your computer and stealing your personal information, like passwords or photos.
• They Block Malware: They can prevent nasty software like viruses or worms from getting into your computer from a dangerous website or link.
• They Control Content: In a school, a firewall can be set up to block websites that are not for learning, like social media or certain game sites, during class time. This helps you focus on your studies!

Tafakari (Reflection) Corner

Fantastic work today! You now understand that a firewall is your computer's digital askari, using a set of rules to protect you from dangers on the internet. It's one of the most important tools for staying safe online.

For you to think about: What other things in your everyday life work like a firewall? Think about your home, your body, or even rules in a game. How do they protect something valuable by filtering what comes in and out?

Keep that curiosity alive, and stay safe online!