Cisco Certified Network Associate (CCNA) Practice Exam

When a host sends a message to an IP address located on a different subnet, it must first send the packet to the default gateway. The MAC address associated with the default gateway is crucial in this scenario, as it serves as the next hop in the process of routing the packet to its destination.

In the context of local area networking, when a device wants to communicate with another device that is outside its local subnet, it doesn't know the MAC address of the remote device. Instead, the device relies on the gateway—often a router configured for routing traffic between different subnets. The host will use an Address Resolution Protocol (ARP) request to find the MAC address of its default gateway, which is typically a router's interface on the local network.

Once the MAC address of the default gateway has been resolved, the host then encapsulates its IP packet within a frame addressed to this MAC address. This is why the correct answer is the MAC address of the default gateway. It ensures that the frame is sent to the correct device that can route it toward its final destination, enabling successful communication across different subnets.