CompTIA Updated N10-009 Exam Questions and Answers by zak

If the user cannot communicate with 192.168.10.1, they might be on a different subnet. Changing the subnet mask to 255.255.255.0 ensures the user and the file server are in the same subnet.

Breakdown of Options:

A. Changing the IPv4 address to 192.168.10.1 – This would conflict with the server ' s IP.

B. Changing the subnet mask to 255.255.255.0 – ✅ Correct answer. Ensures both the user and the server are on the same subnet.

C. Changing the DNS servers – DNS does not affect local network connectivity.

D. Changing the physical address – The MAC address does not impact subnet communication.

To confirm a theory in the troubleshooting process, the technician should duplicate (replicate) the problem under controlled conditions. In the Network+ (N10-009) methodology, confirming a theory means validating that the suspected cause actually produces the observed symptoms. Replicating the issue helps ensure the technician is not chasing a coincidence, and it allows changes to be tested safely (for example, reproducing the issue with a specific user account, endpoint, cable, port, SSID, or configuration). If the problem can be duplicated, the technician can then try targeted actions to see whether the symptoms change in predictable ways—strengthening or disproving the hypothesis.

The other choices occur earlier as part of forming the theory. Identify the symptoms is an initial step to define the problem clearly. Gather information is part of the discovery phase—collect logs, error messages, topology details, and user observations. Determine any changes is also an early step used to correlate recent modifications (patches, new devices, config changes) with the onset of the issue. Those steps help create a theory; duplication helps confirm it before implementing a full fix.

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The most likely issue is a duplex mismatch, which is a well-documented cause of collisions and poor network performance, as outlined in the CompTIA Network+ N10-009 troubleshooting objectives. A duplex mismatch occurs when one end of a network link is configured for full duplex while the other end is operating in half duplex. In half-duplex mode, devices must take turns transmitting and receiving data, which inherently allows for collisions. When paired with a full-duplex device—which expects simultaneous send and receive—collisions and retransmissions occur frequently.

The presence of collisions on a switch interface is a key diagnostic clue. Modern Ethernet switches operating correctly in full duplex should not experience collisions at all. When collisions are observed, it almost always points to a duplex configuration issue, often caused by manual speed/duplex settings on one device and auto-negotiation on the other.

A wrong speed setting may prevent link establishment entirely or cause errors, but it does not typically result in collisions. Jumbo frames can cause packet drops or fragmentation issues, not collisions. An incorrect VLAN configuration affects logical segmentation and connectivity but operates at Layer 2 and does not generate collisions.

CompTIA Network+ emphasizes duplex mismatch as a classic and frequently tested troubleshooting scenario. Correcting it—usually by enabling auto-negotiation on both ends—restores normal, collision-free communication.

•API (Application Programming Interface) enables secure and granular access control, remote management, and logging, making it ideal for network monitoring.

•SNMP (A) is mainly used for device monitoring but lacks centralized logging and user-based privilege control.

•SIEM (C) is a security monitoring tool focused on log collection, not device management.

•SSO (D) is related to authentication, not monitoring.

???? Reference: CompTIA Network+ N10-009 Official Documentation – Network Monitoring & Management Technologies.