See the solution below in Explanation Explanation: R4 Int range et0/0 - 1 Ip ospf authentication message-digest Ip ospf message-digest-key 1 md5 CCNP Router ospf 1 Redistribute connected subnets route-map to-ospf metric-type 1 Copy run start R5 Int range et0/0 - 1 Ip ospf authentication message-digest Ip ospf message-digest-key 1 md5 CCNP Interface eth 0/1 Ip ospf cost 10 Copy run start VERIFICATION:-