N10-009 · topic practice

Network Troubleshooting practice questions

Use this page to practise N10-009 Network Troubleshooting practice questions. The goal is not to memorise dumps, but to understand the concept, review the explanation and improve your exam readiness.

20 questionsDomain: Network Troubleshooting

What the exam tests

What to know about Network Troubleshooting

Network Troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.

How the topic appears in realistic exam-style scenarios.

Which detail in the question changes the correct answer.

How to eliminate plausible but wrong options.

How to connect the question back to the wider exam objective.

Practice set

Network Troubleshooting questions

20 questions · select your answer, then reveal the explanation

Question 1easymultiple choice
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A network administrator is troubleshooting a connectivity issue and suspects the problem is related to the physical cabling. At which layer of the OSI model should the administrator begin their investigation?

Question 2easymultiple choice
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A network administrator needs to schedule a firmware upgrade for a critical switch during a maintenance window. After the upgrade is completed and verified, which document should the administrator update to reflect the new firmware version?

Question 3hardmultiple choice
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A network engineer is troubleshooting connectivity issues between two data center switches that are configured to support jumbo frames with an MTU of 9000. The link is a 10 Gigabit Ethernet fiber connection. Large file transfers fail, but small transfers succeed. What is the most likely cause?

Question 4mediummultiple choice
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A network administrator is troubleshooting communication between two switches connected via a trunk port. The trunk link is up/up, but devices in VLAN 20 cannot communicate across the trunk. The administrator has verified that both switches have VLAN 20 created and that the access ports are configured correctly. Which command should the administrator run on each switch to verify the trunk's allowed VLAN list?

Question 5mediummultiple choice
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A network administrator needs to create a diagram that shows the IP addressing scheme, VLAN assignments, and routing protocols used in the network. This diagram will be used for troubleshooting and future planning. Which type of documentation should the administrator create?

Question 6hardmultiple choice
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A network engineer is troubleshooting intermittent packet loss on a 10 km single-mode fiber link between two buildings. The link lights are on, but the interface shows a high number of CRC errors. The engineer has cleaned the fiber connectors and replaced the patch cables. What should the engineer check NEXT?

Question 7mediummultiple choice
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A network administrator is troubleshooting an intermittent link between two switches connected by single-mode fiber. The interface log shows "Link up / Link down" events multiple times per hour. Which of the following is the most likely cause?

Question 8mediummultiple choice
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A network administrator needs to centrally collect and analyze log messages from multiple routers and switches. Which protocol should be used to forward these log messages to a central server?

Question 9easymultiple choice
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A network administrator wants to ensure all network devices have synchronized time for accurate log correlation and security event analysis. Which protocol should be implemented?

Question 10hardmultiple choice
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A network technician is troubleshooting connectivity between two branch offices connected by a site-to-site VPN. The VPN tunnel shows as active and up. Users at Branch A can ping the VPN gateway IP at Branch B successfully, but they cannot access any servers behind the firewall at Branch B. The firewall at Branch B is stateful and its logs show that traffic from Branch A is being dropped. What is the most likely cause?

Question 11hardmultiple choice
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A network technician is troubleshooting an intermittent connectivity issue between two switches connected via fiber optic cable. The link status shows up/down flapping. The technician checks the optical power levels and finds they are within acceptable range. Which of the following is the most likely cause?

Question 12mediummultiple choice
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A network technician is troubleshooting a switch port that shows a link light but has a high number of CRC errors in the interface statistics. The port is connected to a workstation's network interface card (NIC). Both devices are set to autonegotiate. What is the MOST likely cause of the CRC errors?

Question 13mediummultiple choice
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A network technician is troubleshooting intermittent internet access for a single user. The user’s workstation can ping the default gateway consistently, but web pages fail to load intermittently. Which of the following should the technician check NEXT?

Question 14mediummultiple choice
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A technician is troubleshooting a user's computer that cannot access any network resources. The technician runs ipconfig and sees an IP address of 169.254.18.33 with a subnet mask of 255.255.0.0. The computer is connected to a switch port configured for VLAN 10. The DHCP server is located in a different subnet (VLAN 200) and is reachable via a router. The technician confirms that the switch port is in the correct VLAN and that the cabling is good. Which of the following is the MOST likely cause of the issue?

Question 15mediummultiple choice
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A technician is troubleshooting a user's inability to access the internet. The user can successfully ping the default gateway and internal servers, but cannot ping a public IP address such as 8.8.8.8. The technician checks the firewall logs and confirms that outbound ICMP traffic to 8.8.8.8 is permitted. Which of the following is the most likely cause of the issue?

Question 16mediummultiple choice
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A technician is troubleshooting a connectivity issue. The technician can successfully ping the IP address of a web server (10.10.10.10) from a client, but the client cannot access the web page. Firewall rules allow HTTP traffic. At which OSI layer is the issue most likely occurring?

Question 17mediummultiple choice
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A network technician is troubleshooting a user's inability to connect to the network. The switch port is configured with port security with the default maximum of one MAC address. The user connects a computer and a VoIP phone to the port using the phone's built-in switch. Which of the following will MOST likely occur?

Question 18mediummultiple choice
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A network technician is troubleshooting a workstation that is experiencing intermittent connectivity and slow file transfers. The technician has confirmed that the patch cable passes a cable tester, the switch port is not error-disabled, and the workstation's NIC is configured for autonegotiation. The switch port is also set to autonegotiate. Which of the following should the technician check next?

Question 19hardmultiple choice
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A network technician is troubleshooting a router that is not forwarding packets to a remote destination network. The routing table shows a valid route learned via OSPF. The technician can successfully ping the next-hop IP address from the router. However, packets to the destination network are not being forwarded. Which of the following is the MOST likely cause?

Question 20mediummultiple choice
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A network technician is troubleshooting inter-VLAN routing. Hosts in VLAN 10 can communicate with hosts in VLAN 20, but cannot communicate with hosts in VLAN 30. All VLANs are configured on the same Layer 3 switch with SVIs. Which of the following should the technician verify FIRST?

Watch out for

Common Network Troubleshooting exam traps

  • Answering from memory before reading the full scenario.
  • Missing a constraint such as cost, availability, security, scope or command context.
  • Choosing a broad answer when the question asks for the most specific fix.
  • Ignoring why the wrong options are tempting.

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Focused Network Troubleshooting sessions

Start a Network Troubleshooting only practice session

Every question in these sessions is drawn from the Network Troubleshooting domain — nothing else.

Related practice questions

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Frequently asked questions

What does the N10-009 exam test about Network Troubleshooting?
Network Troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.
How should I use these practice questions?
Select your answer before revealing the explanation. Then read why each option is right or wrong — this active recall approach builds retention far faster than re-reading notes.
Can I practise just Network Troubleshooting questions in a focused session?
Yes — the session launcher on this page draws every question from the Network Troubleshooting domain. Use a 10-question session first to gauge your baseline, then move to 20 or 30 once the weak spots are clear.
Where can I practise other N10-009 topics?
Use the topic links above to move to related areas, or go back to the N10-009 question bank to see all topics.
Are these real exam questions or dumps?
These are original practice questions written to test the same concepts the N10-009 exam covers. They are not copied from any real exam or dump site.