- A Problem-Solving Pattern
- Step 2: Understand the Environment
- Step 3: List Hypotheses
- Step 4: Prioritize Hypotheses and Narrow Focus
- Step 5: Create a Plan of Attack
- Step 6: Act on Your Plan
- Step 7: Test Results
- Step 8: Apply Results of Testing to Hypotheses
- Step 9: Iterate as Needed
- About this Article
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Step 2: Understand the Environment
When you have a clear description of the symptoms, you must be able to understand the environment that the problem occurs in to effectively troubleshoot it. Gaining this understanding is really a twofold job: It requires both identifying the pieces involved in the problem and understanding how those pieces should act when they are not experiencing the problem.
The first task typically means creating a subset of your network map, showing the portions of the network that are involved in the problem. Sometimes this new map will be a logical map, and sometimes you will want to draw it out.
The second task, understanding how things should be behaving, is made much easier if you look at a snapshot of how your network acted before the problem occurred. These snapshots are called baselines and are covered in more detail in Chapter 7 of Networking Linux. In the absence of a baseline, you will need to create a model of the proper behavior of the network from your understanding of its layout, components, and configuration.