Refer to the exhibit. An administrator is trying to configure the switch but receives the error message that is displayed in the exhibit. What is the problem? 'invalid input detected at '^' marker.'

• A. The entire command, configure terminal, must be used.
• B. The administrator is already in global configuration mode.
• C. The administrator must connect via the console port to access global configuration mode.
• D. The administrator must first enter privileged EXEC mode before issuing the command.

Answer: (D)

In Cisco IOS, commands are gated by the mode you’re in, so the system only accepts commands appropriate to that mode. The error “invalid input detected at the ^ marker” shows you typed a command that isn’t recognized in your current mode. To configure a switch, you must first be in privileged EXEC mode, which you access by typing enable and entering a password if prompted. From there, you can enter global configuration mode with configure terminal (or conf t) and issue the configuration commands. If you’re still in user EXEC mode, commands like configure terminal aren’t valid, which triggers that error. The other options don’t fit because you don’t always need to enter the full command from a specific mode, you can access the necessary mode by enable; you can connect in ways other than the console; and being already in global configuration mode would present a different situation.