What is the primary purpose of a default route?

The primary purpose of a default route is to route traffic to any unknown destination IP address. When a router receives a packet for which it does not have a specific route in its routing table, the default route serves as a catch-all pathway guiding packets to their next step. This mechanism is essential for efficient network communication, allowing devices to send traffic that may not have a defined route instead of dropping those packets.

In scenarios where a device is attempting to communicate with an address that is not explicitly known or listed in the routing table, the default route provides a fallback path. This is particularly useful in larger networks or in situations where dynamic routing occurs, and not all destination IP addresses are statically defined.

The other options touch on areas that aren't the focus of a default route. While routing traffic destined for the Internet might imply using the default route in many cases, it doesn't encompass the broader purpose of directing any unknown destination addresses. Managing multicast traffic and prioritizing traffic based on type are concepts that relate more to traffic management and Quality of Service (QoS) strategies rather than the fundamental role of a default route in directing unknown traffic.