Which definition of default route is true?
The correct answer is B. A default route is also known as the gateway of last resort, and it is used by routers to forward packets to destinations outside of their own network. When a router receives a packet and cannot find a specific route in its routing table to forward the packet to the destination network, it will use the default route to send the packet to the next hop router or gateway.
A. A manually configured route is a static route that is created by an administrator and added to the routing table. Static routes are useful when a network has a small number of devices and routes, and they can be used to provide a specific path for traffic. However, they are not default routes.
C. A route to the exact /32 destination address is a host route, which is used to reach a specific IP address on a network. It is not a default route.
D. A dynamic route is learned by a router through a routing protocol, such as OSPF or BGP, and it is not necessarily a default route. Dynamic routes are useful for larger networks where changes in topology can occur frequently, and they provide a way for routers to automatically update their routing tables.
In summary, a default route is a route used when a router cannot find a specific route to forward packets to the destination network, making B the correct answer.