Cisco Certified Network Associate (CCNA) Practice Exam

Which OSPF command is used to activate OSPF on a specific interface?

1. (config-if)#ip ospf enable

2. (config-if)#ip ospf cost NUMBER

3. (config)#router ospf active

4. (config-if)#enable ospf

The correct answer is: (config-if)#ip ospf cost NUMBER

The command used to activate OSPF on a specific interface is indeed not the answer provided. The correct command for activating OSPF on an interface is found among the choices, but primarily revolves around interface configuration. In OSPF configuration, the command specifies the cost of the route, which influences the OSPF path selection process but does not activate OSPF on the interface. The correct command to activate OSPF would generally look like this: "ip ospf process-id area area-id" when configured under the router mode and not as an interface command. For interfaces, simply enabling OSPF requires associating the interface with an OSPF area using the proper syntax in global configuration mode. Understanding how OSPF is configured includes recognizing that the initial step to enable OSPF would involve entering the OSPF router configuration mode, followed by specifying which interfaces are part of OSPF by defining the OSPF area they belong to. The command that specifies the OSPF cost affects the OSPF routing logic, but cost configuration does not directly activate OSPF on an interface. In summary, activating OSPF on an interface primarily relates to associating it with a defined OSPF process and