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):
Note
If you define multiple default routes, the route that has the lowest metric is used. If multiple default routes have the same lowest metric, the system picks one of the routes.The criteria for choosing from multiple routes with the longest matching network mask is set by choosing the relative route priorities.