If a wireless client can see a network but cannot connect, what is a plausible cause?

• A. The client is using antivirus software.
• B. The AP is offline due to power issue.
• C. The MAC address is not recognized by the AP.
• D. The client has an IP address conflict.

Answer: (C)

When a client can see the network but can’t connect, the issue is usually at the authentication/authorization step rather than the radio link. If the access point is enforcing MAC address filtering, it only allows devices with approved MAC addresses to associate. If the client’s MAC isn’t on that list, the AP will reject the connection, so you won’t complete the handshake or obtain network access even though the SSID and beacon are visible. This explains why the network appears but the device can’t connect. Other options don’t fit as well: antivirus software on the client doesn’t typically block initial association; if the AP were offline the network wouldn’t be visible; an IP address conflict happens after you have an IP, not during the initial connection.