Multiple Routes
When there are multiple, conflicting choices of a route to a particular
destination, the router picks the route with the longest matching network mask. If these are
still equal, the router picks the route using the following default criteria (in the order
specified):
- Directly attached network interfaces
- Static routes
- ICMP redirects
- Dynamic routes
- Directly attached network interfaces that are not active.
You can also configure blackhole routes—traffic to these destinations
is silently dropped.
The criteria for choosing from multiple routes with the longest
matching network mask is set by choosing the relative route priorities.