CompTIA N10-009 Online Practice Questions and Exam Preparation

CompTIA N10-009 Online Questions & Answers

• Question 371:

  A support engineer is troubleshooting a network outage that is affecting 3,000 users. The engineer has isolated the issue to the internet firewall. Packet captures confirm that the firewall is blocking the traffic.

  Which of the following is the next step in troubleshooting?

  A. Implement the solution or escalate as necessary
  B. Create a plan of action to resolve the issue and identify potential effects
  C. Establish a theory of probable cause
  D. Document findings, actions, outcomes, and lessons learned throughout the process
  B. Create a plan of action to resolve the issue and identify potential effects

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  Explanation

  The troubleshooting methodology requires following a logical sequence. In this case, the engineer has already identified the problem (firewall blocking traffic) and confirmed it with evidence (packet captures). The next appropriate step is to create a plan of action that outlines how to resolve the issue and considers potential effects.

  Option A: Implementing the solution is premature without planning.

  Option C: Establishing a theory was already completed during problem isolation.

  Option D: Documentation occurs after resolution.

  By carefully planning, the engineer ensures that corrective action won't cause additional outages or security issues, especially given the scale of the incident (3,000 users).

  References:

  Domain: Network Troubleshooting -- Troubleshooting methodology, plan of action.

• Question 372:

  A network administrator needs to add 255 useable IP addresses to the network. A /24 is currently in use.

  Which of the following prefixes would fulfill this need?

  A. /23
  B. /25
  C. /29
  D. /32
  A. /23

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  Explanation

  A /23 subnet provides 512 total addresses, of which 510 are usable (subtracting 2 for network and broadcast addresses). This would satisfy the need for 255 additional addresses.

• Question 373:

  During a security audit, a consulting firm notices inconsistencies between the documentation and the actual environment.

  Which of the following can keep a record of who made the changes and what the changes are?

  A. Network access control
  B. Configuration monitoring
  C. Zero Trust
  D. Syslog
  B. Configuration monitoring

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  Explanation

  Configuration monitoring and management tools (often part of network management systems) maintain version-controlled records of device configurations, track changes, and log who made them. This provides accountability and supports compliance audits.

  Option A: Network access control (NAC) manages endpoint access policies but does not track device config changes.

  Option C: Zero Trust is a security framework requiring strict identity verification, not a configuration tracking tool.

  Option D: Syslog collects system logs, but without a config monitoring system, it does not directly compare documentation to device state.

  References:

  Domain: Network Operations -- Change management, configuration management, auditing.

• Question 374:

  A network administrator determines that some switch ports have more errors present than expected. The administrator traces the cabling associated with these ports.

  Which of the following would most likely be causing the errors?

  A. arp
  B. tracert
  C. nmap
  D. ipconfig
  D. ipconfig

• Question 375:

  A network administrator is migrating a domain to a different provider. As part of the onboarding process, the new provider requests domain ownership proof.

  Which of the following records would the administrator most likely need to create?

  A. A
  B. CNAME
  C. PTR
  D. TXT
  D. TXT

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  Explanation

  The best answer is D. TXT. When a provider asks an administrator to prove ownership of a domain, the most common method is to have the administrator place a specific verification value inside a DNS TXT record. The provider then checks public DNS for that value. If the expected text is present, it confirms that the person managing the migration has control over the domain's DNS settings.

  This matches how TXT records are commonly used in real network environments. They are flexible and can store readable text strings for verification, policy, and security-related purposes. In Network+ study material, TXT records are frequently associated with things like domain validation and email-related configurations such as SPF and other verification mechanisms.

  The other record types do not fit this task. An A record maps a hostname to an IPv4 address. A CNAME points one name to another name. A PTR record is used for reverse DNS, mapping an IP address back to a hostname. None of those are typically created just to prove domain ownership during provider onboarding.

  The key clue is the phrase "domain ownership proof", which strongly points to a TXT record.

• Question 376:

  A systems administrator is investigating why users cannot reach a Linux web server with a browser but can ping the server IP. The server is online, the web server process is running, and the link to the switch is up.

  Which of the following commands should the administrator run on the server first?

  A. traceroute
  B. netstat
  C. tcpdump
  D. arp
  B. netstat

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  Explanation

  The netstat command provides information about network connections, routing tables, interface statistics, masquerade connections, and multicast memberships. Running netstat on the server can help the administrator verify that the web server process is listening on the expected port (e.g., port 80 for HTTP or port 443 for HTTPS) and that there are no issues with network connections. This is a crucial first step in diagnosing why the web server is not accessible via a browser.

  References:

  CompTIA Network+ study materials.

• Question 377:

  Which of the following internal routing protocols is best characterized as having fast convergence and being loop-free?

  A. BGP
  B. STP
  C. OSPF
  D. RIP
  C. OSPF

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  Explanation

  The correct answer is OSPF (Open Shortest Path First). OSPF is a link-state routing protocol known for its fast convergence and use of the Dijkstra algorithm to calculate the shortest loop-free path. It efficiently scales to large enterprise networks and avoids routing loops by maintaining a complete topology map.

  Option A: BGP is primarily an external routing protocol used between ISPs, not internal.

  Option B: STP is not a routing protocol; it prevents loops at Layer 2.

  Option D: RIP is an older distance-vector protocol with slower convergence and a maximum hop limit of 15.

  OSPF's design makes it the preferred internal gateway protocol (IGP) for medium-to-large organizations requiring speed and loop-free reliability.

  References:

  Domain: Networking Concepts -- IGPs, OSPF, routing protocols.

• Question 378:

  A Chief Information Officer is concerned about environmental issues in the data center at corporate headquarters.

  Which of the following are the most common sensors installed in a data center? (Choose two.)

  A. Carbon monoxide
  B. Air flow
  C. Flooding
  D. Humidity
  E. Electrical
  F. Temperature
  D. Humidity
  F. Temperature

• Question 379:

  Which of the following should an installer orient a port-side exhaust to when installing equipment?

  A. The patch panel
  B. The front of the IDF
  C. The warm aisle
  D. The administrator console
  C. The warm aisle

• Question 380:

  A network technician is designing a LAN for a new facility. The company is expecting more than 300 devices to connect to the network.

  Which of the following masks will provide the most efficient subnet?

  A. 255.255.0.0
  B. 255.255.192.0
  C. 255.255.254.0
  D. 255.255.255.254
  C. 255.255.254.0