Cisco IOS password recovery follow-up: After you successfully complete the password recovery procedure and want to return the router to normal boot behavior, what configuration register value should be set?

Introduction / Context:
In Cisco routers, the configuration register controls key boot behaviors such as where to load the IOS and whether to ignore the startup configuration in NVRAM. During password recovery, the register is temporarily changed so the router ignores the saved configuration; after recovery, you must restore the normal value.

Given Data / Assumptions:

• Password recovery has been completed.
• The goal is to restore normal operation (load startup-config on boot).
• Standard Cisco IOS behavior is assumed.

Concept / Approach:

The typical normal-operation value is 0x2102. The commonly used recovery value is 0x2142, which instructs the device to ignore NVRAM at the next boot so you can bypass passwords. Once finished, set the register back to 0x2102 so the router again loads the saved configuration on startup.

Step-by-Step Solution:

Verification / Alternative check:

Use show version to verify the current configuration register value displayed near the end of the output. Confirm that on reboot the router reads the startup configuration as expected.

Why Other Options Are Wrong:

0x2142 (D) is the temporary recovery setting that ignores NVRAM.

0x2100 and 0x2101 (A, B) alter boot behavior (e.g., ROMMON or image selection) and are not the default for normal operations.

Common Pitfalls:

Forgetting to change 0x2142 back to 0x2102, causing the router to keep ignoring the startup-config and booting blank.

Final Answer:

0x2102