N10-009 domain - 24% of the exam

Network Troubleshooting

Network Troubleshooting is 24% of the CompTIA Network+ (N10-009) exam. These are the objectives it covers, each with practice questions and worked explanations.

Objectives in this domain

Sample question from this domain

Free sampleNetwork Troubleshootingeasy

A technician troubleshooting a slow 100 Mbps server link has just formed the idea that a duplex mismatch between the switch port and the server NIC is the likely cause. Following the CompTIA seven-step troubleshooting methodology, what should the technician do next?

  • ATest the theory by checking the interface counters and duplex settings on both ends to confirm the mismatch. Correct
  • BImplement the solution by hard-coding both interfaces to the same speed and duplex.
  • CDocument the findings and the corrective action taken in the ticketing system.
  • DEstablish a plan of action and identify the potential effects of changing the duplex settings.
After establishing a theory of probable cause, the next methodology step is to test that theory before planning or implementing any fix. The CompTIA method sequences theory work as establish, then test, then plan, then implement, so a freshly formed theory must be tested to confirm the cause before any change is made.

Why A is correct: After a theory of probable cause is established, the methodology's next step is to test that theory to determine whether it is actually the cause.

Why B is wrong: This is the eventual corrective action and feels efficient, but implementing a change comes only after the theory has been tested and a plan of action has been established.

Why C is wrong: Documentation is a real methodology step, but it is the final one performed after the fix is verified, not the step that follows forming a theory.

Why D is wrong: Planning is a genuine step, but it belongs after the theory is confirmed by testing, so building a plan now skips the required test step.

Other domains in this exam

See also the N10-009 cert hub, the study guide, and the cheat sheet.

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