OSI and TCP/IP Models
Learn how networks are structured and how data flows using the OSI and TCP/IP models.
OSI and TCP/IP Models is a free Ethical Hacking Academy lesson on CoddyKit — lesson 1 of 3. 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 Ethical Hacking Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
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Welcome to OSI and TCP/IP Models
Understanding these models helps us grasp how data moves across networks.
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What is the OSI Model?
The OSI (Open Systems Interconnection) model is a conceptual framework used to understand network communication.
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OSI Model Layers
- Physical - Transmits raw data (bits).
- Data Link - Handles MAC addressing and error detection.
- Network - Determines paths using IP addresses.
- Transport - Ensures end-to-end communication.
- Session - Manages communication sessions.
- Presentation - Formats and encrypts data.
- Application - Interfaces with user applications.
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What is the TCP/IP Model?
The TCP/IP model is a simplified model for real-world networking.
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TCP/IP Model Layers
- Network Access - Physical and data link layer functions.
- Internet - Handles addressing and routing.
- Transport - Ensures reliable communication.
- Application - Supports user applications.
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Key Differences Between OSI and TCP/IP
- OSI has 7 layers, TCP/IP has 4.
- OSI is theoretical, TCP/IP is practical.
- TCP/IP is used in real networks today.
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Why Do These Models Matter?
They help troubleshoot networks and understand protocols like TCP, UDP, and IP.
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Real-World Applications
Understanding these models helps in configuring routers, firewalls, and diagnosing network issues.
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Summary
OSI and TCP/IP models are essential for understanding how networks function and troubleshoot issues effectively.
Frequently asked questions
Is the “OSI and TCP/IP Models” lesson free?
Yes — the full text of “OSI and TCP/IP Models” is free to read here on the web, and the Ethical Hacking Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Ethical Hacking Academy course, upgrade to CoddyKit PRO.
What will I learn in “OSI and TCP/IP Models”?
Learn how networks are structured and how data flows using the OSI and TCP/IP models. You practise Ethical Hacking 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 Ethical Hacking Academy?
No prior experience is required. Ethical Hacking Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 3, so you can start here or from the beginning and move at your own pace.
How long does the “OSI and TCP/IP Models” 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 Ethical Hacking Academy lesson?
Yes. Every Ethical Hacking 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
- OSI and TCP/IP Models
- Common Network Protocols
- Network Topologies & Devices