Cisco Certified Network Associate (CCNA) Practice Exam

What command finalizes changes made in the router configuration mode?

1. save configuration

2. end

3. exit

4. copy running-config startup-config

The correct answer is: copy running-config startup-config

The command that finalizes changes made in the router configuration mode is the one that saves the current running configuration to the startup configuration file. This is crucial because the changes made in configuration mode are temporarily stored in the router's RAM as the running configuration. When the command to copy the running configuration to the startup configuration is executed, it ensures that all modifications will persist even after the device is rebooted. This means that when the router powers off and on again, it will load the saved startup configuration, which includes all the changes made during the session. In contrast, the other commands serve different purposes. While "end" typically exits the configuration mode, it does not save any changes. "Exit" also leaves the current mode but similarly does not save anything. The command to "save configuration" might imply saving, but in Cisco IOS, the appropriate command is the copying of running to startup configuration for that finalization process.