N10-009 Question 200
Single answerConfiguration management: Production configuration, Backup configuration, Baseline/golden configurationA network administrator applied a security hardening update to a core switch late at night. The next morning, users in several departments report intermittent connectivity and missing access to multiple VLANs. The administrator confirms the issue started immediately after the change. The company keeps a documented production configuration for each device, nightly backups of device configurations, and a baseline (golden) configuration template for standard switch deployments. To restore service as quickly as possible while minimizing the risk of introducing additional errors, what should the administrator do FIRST?
- A
Replace the current switch configuration with the most recent known-good backup configuration for that switch, then validate connectivity
- B
Apply the baseline (golden) configuration template to the switch because it represents the approved standard for all switches
- C
Manually compare the running configuration to the production documentation and change settings one by one during business hours
- D
Reboot the switch and allow it to reload the startup configuration, because the issue is likely temporary
- E
Deploy the configuration from another core switch with a similar role, since the devices should be mostly identical
Show answer and explanation
Correct answer: A
Explanation
This question tests the distinction between production configuration, backup configuration, and baseline/golden configuration. In real-world network operations, a production configuration is the device's approved live configuration currently supporting business services. A backup configuration is a saved copy of a known-good device configuration used for recovery after failed changes, corruption, or hardware replacement. A baseline or golden configuration is a standard reference template used to deploy new devices, audit compliance, and reduce configuration drift.
Because the outage began immediately after a change, best practice is to use the most recent known-good backup for that specific switch to restore service quickly. This aligns with common operational guidance in vendor documentation from Cisco, Juniper, Aruba, and others, which emphasizes maintaining current configuration backups and using rollback or restore procedures after failed changes. Golden configurations are valuable for standardization and compliance, but they do not always include all production-specific details required for a specific device. Effective change management also includes validating the restored state, documenting the incident, and testing the hardening change in a non-production environment before reapplying it.
- A. Correct.
Correct. When a problem begins immediately after a configuration change, the fastest and lowest-risk first step is typically to restore the most recent known-good backup configuration for that specific device. A device-specific backup preserves the switch's intended production state, including interface assignments, VLAN settings, uplinks, routing or management settings, and any unique local parameters. After restoration, the administrator should validate connectivity and then investigate the failed hardening change through formal change control.
- B. Incorrect.
Incorrect. A baseline or golden configuration is a standardized template used to build or validate devices against an approved configuration standard. It is not usually the best first choice for immediate restoration of a production outage on a specific switch, because it may not contain all site-specific or device-specific settings currently required in production. Applying it directly could remove necessary customizations and worsen the outage.
- C. Incorrect.
Incorrect. Comparing the running configuration to documentation can be useful for troubleshooting, but it is slower and riskier during an active outage caused by a recent change. Making manual edits one by one increases the chance of additional mistakes and prolongs downtime. In an outage scenario, restoring a known-good backup is generally a better first response than performing live incremental troubleshooting on a critical device.
- D. Incorrect.
Incorrect. Rebooting the switch does not guarantee recovery. If the problematic changes were saved to startup configuration, the switch will simply reload the bad configuration. Even if the running and startup configurations differ, rebooting a core switch during production hours introduces unnecessary risk and additional disruption without addressing the root cause of a bad recent change.
- E. Incorrect.
Incorrect. Copying a configuration from another core switch is risky because even similar devices often have different interface mappings, VLAN trunks, IP addresses, routing roles, spanning tree priorities, management settings, or hardware-specific details. This could create duplicate IPs, break uplinks, or introduce inconsistent production behavior. A device-specific backup is much safer.