Network Segmentation
Isolate sensitive zones.
Network Segmentation is a free Cyber Security Academy lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Cyber Security Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What Is Segmentation
Network segmentation divides a network into smaller, isolated zones.
Each zone is separated by controls so traffic between them can be inspected and restricted.
The Flat Network Problem
A flat network puts every device in one big zone.
If an attacker breaches one machine, they can freely reach all the others. Segmentation breaks that path.
Limiting Lateral Movement
Lateral movement is how attackers spread from the first compromised host to others.
Segmentation confines them to one zone, buying time for detection and response.
VLANs
A VLAN (virtual LAN) logically splits one physical switch into separate networks.
Devices on different VLANs cannot talk directly without passing through a router or firewall.
Subnets and Routing
Each zone usually has its own subnet, a defined range of IP addresses.
Traffic between subnets is routed through a gateway where firewall rules can inspect and filter it.
Zone examples:
Users: 10.10.1.0/24
Servers: 10.10.2.0/24
Guests: 10.10.9.0/24Grouping by Function
Common zones reflect roles and risk.
- User workstations
- Servers and databases
- Guest Wi-Fi
- Industrial or IoT devices
Sensitive systems get the strictest isolation.
Protecting Sensitive Data
High-value systems, like a database holding customer records, belong in a tightly controlled zone.
Only specific applications, from specific sources, are allowed to reach them.
Microsegmentation
Microsegmentation takes the idea further, isolating individual workloads or even single machines.
Policies follow each workload, so even servers in the same zone cannot talk unless explicitly permitted.
Segmentation and Compliance
Standards often require isolation of sensitive systems.
For example, payment-card rules expect cardholder data to live in a segmented zone, separate from the general network.
Inter-Zone Rules
The value of segmentation comes from the controls between zones.
Use default deny between zones and allow only the specific flows each business need requires.
Monitoring Boundaries
Zone boundaries are ideal places to watch for trouble.
Logging and intrusion detection at these chokepoints reveal attempts to move between zones, an early sign of an attack.
Quick Check
Test your understanding of network segmentation.
Recap
Network segmentation:
- Splits a flat network into isolated zones (VLANs, subnets)
- Limits lateral movement and protects sensitive data
- Uses default-deny inter-zone rules and boundary monitoring
Microsegmentation isolates down to individual workloads.
Frequently asked questions
Is the “Network Segmentation” lesson free?
Yes — the full text of “Network Segmentation” is free to read here on the web, and the Cyber Security Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Cyber Security Academy course, upgrade to CoddyKit PRO.
What will I learn in “Network Segmentation”?
Isolate sensitive zones. You practise Cyber Security Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Cyber Security Academy?
No prior experience is required. Cyber Security Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Network Segmentation” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Cyber Security Academy lesson?
Yes. Every Cyber Security Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Firewall Types
- Rules and Policies
- Network Segmentation
- DMZ Design