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.
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
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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
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Every question in these sessions is drawn from the Network Troubleshooting domain — nothing else.
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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.
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Exam traps to avoid
- ▸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.