N10-009 Network Security Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Access the switch and enter privileged EXEC mode, then enter global configuration mode, then create the VLAN, then assign interfaces to the VLAN.

  Why this is correct

  This sequence accurately reflects the logical progression for configuring a VLAN on most managed switches, particularly Cisco IOS-based devices. Initial access and privileged EXEC mode are prerequisites for any configuration changes. Global configuration mode is where system-wide parameters, including VLAN definitions, are established. Only after the VLAN is explicitly defined can individual interfaces be configured to operate within that specific VLAN, ensuring proper network segmentation.

• ✗

  Access the switch and enter privileged EXEC mode, then create the VLAN, then enter global configuration mode, then assign interfaces to the VLAN.

  Why it's wrong here

  This order is incorrect because the command to create a VLAN (e.g., `vlan <VLAN_ID>`) is a global configuration command. Attempting to execute it directly from privileged EXEC mode would result in an "Invalid input detected" or similar error message, as the command context is incorrect. Global configuration mode is essential for defining new VLANs before they can be utilized by interfaces or other configurations.

• ✗

  Enter global configuration mode, then access the switch and enter privileged EXEC mode, then create the VLAN, then assign interfaces to the VLAN.

  Why it's wrong here

  This sequence is fundamentally flawed as it attempts to enter global configuration mode (`configure terminal`) before even accessing the switch and entering privileged EXEC mode (`enable`). A user must first establish a session with the switch and elevate their privileges to privileged EXEC mode to gain the necessary permissions to enter global configuration mode. The initial steps of accessing the device and elevating privileges are non-negotiable prerequisites for any configuration changes.

• ✗

  Access the switch and enter privileged EXEC mode, then enter global configuration mode, then assign interfaces to the VLAN, then create the VLAN.

  Why it's wrong here

  This order is incorrect because an interface cannot be assigned to a VLAN that does not yet exist within the switch's configuration. When attempting to configure an interface with a non-existent VLAN ID (e.g., `switchport access vlan <VLAN_ID>`), the switch would typically either report an error indicating the VLAN is not found or, in some cases, dynamically create the VLAN if that feature is enabled. Explicitly creating the VLAN first ensures it is available for assignment and prevents potential configuration failures.

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