Network Troubleshooting

When network issues arise, a systematic approach to troubleshooting saves time and reduces guesswork. This lesson covers a structured methodology, essential tools, and common problems with their solutions.

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The Troubleshooting Methodology

Follow a layered, bottom-up approach using the OSI model:

Step-by-Step Process

1. Identify the problem — What is the symptom? Who is affected? When did it start?
2. Gather information — Collect logs, error messages, and topology diagrams
3. Develop a theory — Based on the evidence, what layer is likely affected?
4. Test the theory — Use tools and commands to confirm or eliminate
5. Implement a solution — Apply the fix
6. Verify — Confirm the issue is resolved and no new problems were introduced
7. Document — Record the problem, cause, and solution for future reference

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Bottom-Up Troubleshooting with the OSI Model