Question 440
During a post-incident review at a regional data center, the original problem was: A static one-to-one NAT entry accidentally reuses a public IP already assigned to another service, causing inconsistent session destinations. Which preventive practice most directly addresses its cause?
Explanation
Correct Answer
Audit public address allocation before adding static NAT rules. This control reduces recurrence of the documented mechanism: Ambiguous NAT translations can create unpredictable matches and address conflicts. It creates a repeatable check around the needed response: Resolve overlapping translation mappings and assign a unique approved public address or appropriately distinguished service port.
Incorrect Answers
Test inside and outside access to hosted public services before cutover. That safeguard addresses another potential failure: A remote branch allows internal clients to access a web service via its public VIP, but hairpin requests fail because required U-turn NAT is absent. It is not the most targeted recurring control for the described cause: Ambiguous NAT translations can create unpredictable matches and address conflicts.
Test full session establishment rather than only initial connection success. That safeguard addresses another potential failure: A protocol uses multiple media connections, but the admin believes translating only a signaling port guarantees the application's entire session. It is not the most targeted recurring control for the described cause: Ambiguous NAT translations can create unpredictable matches and address conflicts.
Capture representative session path and NAT rule matches before promotion. That safeguard addresses another potential failure: A static source translation is created for a server farm, but egress traffic follows an unexpected route and misses the intended NAT rule. It is not the most targeted recurring control for the described cause: Ambiguous NAT translations can create unpredictable matches and address conflicts.