CompTIA Network+ (N10-007) — Question 587

An ISP technician gets a call from a business that just changed equipment but can no longer connect to the Internet. The technician checks the ARP table on the
ISP switch, and there is no corresponding MAC address present. Instead, the entry is `Incomplete`. Which of the following could cause this condition?

Answer options

• A. VLAN mismatch
• B. Duplex/Speed mismatch
• C. Duplicate IP address
• D. TX/RX reverse

Correct answer: B

Explanation

The 'Incomplete' status in the ARP table often indicates a communication problem between devices, which is commonly caused by a Duplex/Speed mismatch. Other options like VLAN mismatch, duplicate IP address, or TX/RX reverse issues may lead to connectivity problems, but they do not specifically result in an incomplete ARP entry.