Refer to the exhibit. Why is the 140.140.0.0 network not used as the gateway of last resort even though it is configured first?
正解:B
Explanation/Reference: Explanation: In the routing table of R3, we can only see the route 130.130.0.0/16 is learned via EIGRP (marked with D) and is being chosen as the "Gateway of last resort". The route to 140.140.0.0 is not present in the routing table so the command "ip default-network 140.140.0.0" has no effect. Remember that a route must appear in the routing table (via static route or learned via a routing protocol before it can be set as "Gateway of last resort" by the "ip default-network" command.