In a shared Ethernet environment, which statement describes how frames not addressed to a machine are handled?

• A. Frames are broadcast to all devices
• B. Frames are forwarded to the appropriate switch port
• C. Frames are encrypted before sending
• D. Other machines compare the frame's destination MAC address with their own and discard unmatched frames

Answer: (D)

In a shared Ethernet segment, the frame is placed on the common wire so every device on that segment can see it. Each network interface card then checks the frame’s destination MAC address and will accept and pass up the frame only if it matches its own address (or if the frame is broadcast/multicast). If the destination doesn’t match, the NIC discards the frame. This is exactly what happens with frames not addressed to a particular machine: they are ignored by that machine because their destination MAC doesn’t match. The other statements aren’t accurate for a shared Ethernet context: there isn’t a switch port to forward to, encryption isn’t part of the normal handling, and while the frame is seen by all devices on the segment, the actual filtering is done by each NIC based on the destination MAC.