What Does Route Poisoning Mean?
Route poisoning is a method that prevents a certain network from sending data packets to a path destination that has already become invalid. This is done when a distance vector routing protocol sees an invalid route or one with large routing loops. A route is considered unreachable if it exceeds the maximum allowed. So the routing protocol simply informs all the routers connected in the network that a certain path is invalid by saying that it has a hop count that exceeds the maximum allowable.
Techopedia Explains Route Poisoning
For example, in Routing Information Protocol (RIP) the maximum is 15, so the hop count of the route to be poisoned is set to 16, making this path unreachable and will no longer be used for routing data.
