A technician is troubleshooting a wireless network issue that is intermittently affecting two users. Which of the following is the most likely cause of the issue?

A duplicate IP address conflict is the most likely cause for an intermittent network issue affecting exactly two users. When two devices on the same network have the same IP address, the network switch and router become confused about which device should receive incoming data packets. This results in packets being sent to the wrong device, causing both users to experience sporadic connection drops and unreliable network access. This symptomology directly matches the "intermittent" and "two users" criteria described in the scenario.

A. Incorrect SSID: This would prevent the users from connecting to the wireless network at all, rather than causing an intermittent problem.
B. Offline DHCP server: This would prevent new devices from obtaining an IP address and would likely affect many more than two users as their leases expire.
C. Corrupted router firmware: This would typically cause more global and persistent issues, such as frequent router reboots or complete network failure for all users.

1. CompTIA A+ Core 1 (220-1101) Exam Objectives, Version 5.0, Section 2.7: "Given a scenario, troubleshoot common network problems." This section lists "IP conflict" as a common network problem and "Intermittent wireless connectivity" as a common symptom, directly linking the cause and effect in the question.

2. Microsoft Corporation. (2023). Troubleshoot TCP/IP connectivity. Microsoft Learn. In the "Troubleshoot IP address configuration" section, it is noted that a duplicate IP address on the network is a common cause of TCP/IP connection problems, where communication may fail for one or both of the conflicting devices.

3. Kurose, J. F., & Ross, K. W. (2021). Computer Networking: A Top-Down Approach (8th ed.). Pearson. In Chapter 4, "The Network Layer: Data Plane," the text explains the fundamental principle that each host interface on a network must have a unique IP address for proper datagram delivery (Section 4.4.1). A violation of this uniqueness leads to routing ambiguity and connectivity failures.