Network Troubleshooting

🔧 Network Troubleshooting

🔍 Step 1: Identify the Problem

• First, observe the symptoms (e.g., browser not opening websites, local file sharing not working).
• Communicate with the user clearly: Has anything changed recently? Has this issue occurred before?
• Check the scope of the problem: Is it affecting one system or the whole network?
• Try to reproduce the problem: Attempt to recreate the issue to better understand it.
• Pro Tip: If there are multiple issues, address them one by one, based on priority.

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🤔 Step 2: Develop a Theory of Probable Cause

• Make an educated guess based on the symptoms.
• Use the OSI model to structure your approach:
  • Bottom-to-Top: If it’s likely a hardware issue (e.g., loose cable, faulty NIC).
  • Top-to-Bottom: If it’s clearly a software/configuration issue (e.g., invalid credentials).
• Apply “divide and conquer”: Eliminate one possibility at a time to narrow down the root cause.

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🧪 Step 3: Test the Theory to Determine the Cause

• Before implementing any solution, test your theory to verify it’s the actual cause.
• If the fix is complex or expensive, validate the theory first.
• If your guess is wrong, don’t worry — try the next theory or escalate the issue to the next support tier.

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🧠 Step 4: Establish a Plan of Action

• Prepare a proper action plan before applying any fix.
• Evaluate the impact of the fix: Will it affect users, applications, or data?
• Follow change management protocols, especially in production:
  • Include the need for the change, cost, mitigation of disruption, and rollback strategy.

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🛠️ Step 5: Implement the Solution or Escalate

• Inform affected users ahead of time: “There might be a short disruption.”
• Take backups of all important data and current system configurations.
• Make one change at a time and verify if the issue is resolved before proceeding.
• If the issue is outside your scope or responsibility, escalate it to someone with appropriate authority or technical access.

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✅ Step 6: Verify Full System Functionality & Apply Preventive Measures

• Perform complete system testing after applying the fix.
• Ask the user to test it too — different permissions and configurations may impact their experience.
• Monitor the system over the next few days to ensure stability.
• Think ahead: What can prevent this issue from happening again?
  • More preventive maintenance? Add a network monitoring tool?

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📝 Step 7: Document Findings, Actions & Outcomes

• Log all actions in the organization’s help desk or ticket tracking system:
  • Include: who reported it, department, contact info, time of report, symptoms, resolution steps, technician name, and time taken.
• If a unique solution or key learning was involved, record it for future reference.
• This documentation helps build a knowledge base for the entire IT team to use later.

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🧪 Real-Life Example – Case Summary

🖥️ Problem: Desktop couldn’t access the internet or local network resources.

🧠 Theory: A technician was working near the desk the previous evening — possibly unplugged cable.

✅ Test: Found the cable unplugged and lying on the floor.

🔌 Fix: Reconnected the cable — connection restored.

📝 Documentation: Simple fix, so just verbally informed nearby colleagues. But in a real-world setting, always log it formally.

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🎯 Key Takeaways for Quick Review

• Bottom-up = suspect hardware issues first.
• Top-down = suspect software or configuration errors.
• Always document your actions and resolution.
• Test before applying any fix.
• Notify users, back up everything, and plan for rollback.
• After fixing the problem, think prevention — monitoring, documentation, and maintenance.