Cisco NVRAM Cleanup — Deleting the Saved Startup Configuration If you need to remove the configuration stored in NVRAM (startup-config) on a Cisco router to return it to default settings, which command would you use?

Difficulty: Easy

Correct Answer: erase startup

Explanation:


Introduction / Context:
Clearing the saved configuration (startup-config) is often necessary before repurposing a device or troubleshooting. On classic IOS, several syntaxes exist; exam-style questions commonly reference the shorthand form used to erase NVRAM content that is loaded at the next boot.


Given Data / Assumptions:

  • The goal is to delete the contents of NVRAM (startup-config), not the current running-config in RAM.
  • The device is a Cisco router using traditional IOS syntax.
  • We want the canonical command recognized in entry-level administration tasks.


Concept / Approach:
The saved configuration that persists across reloads is the startup-config stored in NVRAM (or its flash-backed equivalent). To remove it, classic IOS accepts commands such as erase startup or the more explicit erase startup-config, as well as the legacy write erase. After erasing, a reload boots the device without a saved configuration and triggers the initial configuration dialog.


Step-by-Step Solution:
From privileged EXEC mode, issue: erase startupConfirm the prompt to erase NVRAM contents.Reload the device: reloadUpon boot, skip initial config or reconfigure as needed.


Verification / Alternative check:
Run show startup-config after erasure (or before reload) to verify it is empty or not present. After reload, show running-config shows default minimal settings.


Why Other Options Are Wrong:

  • erase nvram/delete nvram: Not standard modern IOS commands; syntax varies and may not be valid.
  • erase running: A running-config is in RAM and is cleared by reload, not by this command.
  • erase startup-config: Valid on many IOS versions; however, the keyed option provided as the exam's expected shorthand here is erase startup.


Common Pitfalls:
Erasing the wrong configuration (confusing running vs. startup) or forgetting to reload, leaving the old running-config active until reboot.


Final Answer:
erase startup

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