What is a Discard Route?

A Discard Route is specifically defined as a route that points to a null interface, often referred to as a "black hole." This type of route is used to effectively drop packets destined for a specific network or IP address without sending them out of the router. By configuring a Discard Route, network administrators can prevent unwanted traffic from being forwarded to unreachable destinations or to mitigate potential attacks such as DoS (Denial of Service).

Using a null interface ensures that no resources are wasted on processing or forwarding packets that should not be forwarded. For instance, if certain IP addresses are not in use, they can be black-holed with a Discard Route, thereby enhancing overall network security and performance.

This routing decision is useful in scenarios where a certain subnet is no longer valid or has been reassigned, allowing the network to manage traffic efficiently without the overhead of handling irrelevant packets.