Network Troubleshooting Methodology

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CompTIA Network+ Troubleshooting Methodology

1. Identify the problem
   • Gather information
   • Question users
   • Identify symptoms
   • Determine if anything has changed
   • Duplicate the problem, if possible
   • Approach multiple problems individually
2. Establish a theory of probable cause
   • Question the obvious
   • Consider multiple approaches:
     • top-to-bottom OSI model
     • bottom-to-top OSI model
     • Divide and conquer OSI model
3. Test the theory to determine cause
   • If theory confirmed, determine next steps to resolve problem
   • If theory is not confirmed, establish a new theory or escalate
4. Establish a plan of action to resolve the problem and identify potential effects
5. Implement the solution or escalate as necessary
6. Verify full system functionality and implement preventative measures if applicable
7. Document findings, actions, outcomes, and lessons throughout the process

Troubleshooting Tips

• Identify the Problem
  • Gather Information
    • identify the location and scope of the problem
      • scope helps establish priority and source of the problem
  • Question Users
    • Ask open questions
    • Ask closed questions
  • Identify Symptoms and Duplicate the Problem
    • symptoms are facts and clues in the affected system that can be correlated with known causes and issues
    • To identify symptoms:
      • make a physical inspection
      • check system logs or diagnostic software for information
      • Duplicate the problem on the user’s system or a test system
  • Determine If Anything Has Changed
    • two key questions to ask:
      • Did it ever work?
      • What has changed since it was last working?
• Establish a Plan of Action
  • 3 solutions to any problem:
    • Repair
    • Replace
    • Accept