EC0-350 Question #442: Real Exam Question with Answer & Explanation

Paul has just finished setting up his wireless network. He has enabled numerous security features such as changing the default SSID, enabling WPA encryption, and enabling MAC filtering on his wireless router. Paul notices that when he uses his wireless connection, the speed is sometimes 54 Mbps and sometimes it is only 24Mbps or less. Paul connects to his wireless router's management utility and notices that a machine with an unfamiliar name is connected through his wireless connection. Paul checks the router's logs and notices that the unfamiliar machine has the same MAC address as his laptop. What is Paul seeing here?