True or False: A router uses only MAC addresses for addressing information.

A router does not rely solely on MAC addresses for addressing information, which is why the answer is false. Routers primarily use IP addresses for routing packets between different networks. In the network hierarchy, MAC addresses operate at the data link layer (Layer 2), which is responsible for local addressing within a single network segment. However, routers work at the network layer (Layer 3) and utilize IP addresses to determine the best path for forwarding packets between networked devices, which can be located on different networks.

While MAC addresses are essential for communication within a local area network (LAN), they do not provide the necessary information for routing across broader networks, such as the internet. Routers typically maintain a routing table that maps IP addresses to their respective physical network interfaces, allowing them to efficiently direct traffic to its intended destination. This distinction between Layer 2 and Layer 3 functions underlines why the statement is false.