What is the definition of a default route?

A default route is defined as a route that matches all unspecified IP addresses. This means that when a router receives a packet destined for an IP address that does not match any of its known routes in the routing table, it will use the default route to forward the packet.

Default routes are particularly useful in simplifying routing tables, as they provide a catch-all path for traffic that has no specific route defined. This is commonly utilized in scenarios where a network may not have the resources or need to maintain an exhaustive list of routes for every possible destination. By designating a default route, the network can efficiently manage traffic without overloading the routing table with details for every individual destination.

In practical applications, this serves as a way to direct outgoing traffic to a general destination, often leading to an Internet egress point or another part of the internal network. In larger configurations, having a default route helps ensure that all packets are addressed to a known next hop, improving the overall routing efficiency.