Lesson 4.1 — What firewalls are protecting: boundary firewalls, routers and software firewalls

This lesson introduces the Cyber Essentials firewall control and explains what firewalls are protecting.

What You'll Be Able to Do

By the end of this lesson, you will be able to:

identify the firewall protection used across the in-scope environment
understand when boundary firewalls and software firewalls apply
explain how remote and mobile workers are protected
prepare a firewall protection map for the rest of the A4 module.

Why This Matters

It helps the learner understand the difference between boundary firewalls, internet routers with firewall functions, cloud firewalls and software firewalls on user devices before they begin answering the detailed firewall questions.

The most common problems are:

assuming the office firewall protects all remote workers;
assuming a router has firewall protection without checking;
ignoring software firewalls on laptops and desktops;
ignoring software firewalls on servers where applicable;

The Core Rule

Firewalls control network access and help protect organisational devices, networks and services from unauthorised access.

Cyber Essentials expects in-scope devices and networks to be protected appropriately, including through boundary firewalls, router/firewalls, software firewalls and cloud firewall controls where relevant.

Common Mistakes

assuming the office firewall protects all remote workers;
assuming a router has firewall protection without checking;
ignoring software firewalls on laptops and desktops;
ignoring software firewalls on servers where applicable;
listing home routers as organisational firewalls;
forgetting business-provided routers for remote workers;

Copy This

Work through the workbook activity for this lesson. Each question maps directly to the CE questionnaire.

Quick Checklist

Before moving on, make sure you can say yes to these:

[ ] What is the main purpose of the Cyber Essentials firewall control?
[ ] What is a boundary firewall?
[ ] Can an internet router provide firewall protection?
[ ] What is a software firewall?
[ ] Why are software firewalls especially important for remote workers?

Your Action

Do this now — it takes 10–20 minutes.

Identify all firewalls protecting your network — hardware, software, and cloud. List them by type and location. Add to Section F (Firewalls) of your evidence document.

Key Takeaway

Know what is protected, how it is protected, who manages it and where the evidence is.

Your Workbook Activity

Complete: Firewall protection map

Next Lesson

In the next lesson: Default passwords, firewall admin accounts and remote administration access