Cisco Certified Network Associate (CCNA) Practice Exam

What command is executed after configuring interfaces for EIGRP for IPv6 to ensure they are active?

1. (config-if)#no shutdown

2. (config-router)#maximum-paths NUMBER

3. (config-if)#shutdown

4. (config)#copy run start

The correct answer is: (config-if)#no shutdown

The command that is executed to ensure that interfaces configured for EIGRP (Enhanced Interior Gateway Routing Protocol) for IPv6 are active is "no shutdown." This command is essential in activating an interface that has been administratively shut down. In networking, interfaces can be disabled for a variety of reasons, and issuing the "no shutdown" command is what brings them back into an operational state, allowing the routing protocol to function correctly. Without active interfaces, EIGRP won't be able to establish neighbor relationships or participate in routing updates, effectively rendering it non-functional. Other commands serve different purposes within the configuration context. For instance, the command for maximum paths defines the number of equal-cost paths used for load balancing but does not directly concern interface activation. Similarly, issuing a shutdown command would disable the interface instead of activating it, creating the opposite effect of what is needed. Finally, the command to copy the running configuration to startup memory is crucial for saving changes but does not influence the operational status of interfaces in EIGRP at the moment it is needed. Therefore, the correct choice emphasizes the importance of ensuring that interfaces are ready to participate in EIGRP by executing the "no shutdown" command.