Cisco NAT operations: Which IOS command shows real-time, live translation events occurring on the router?
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Ashow ip nat translations
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Bshow ip nat statistics
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Cdebug ip nat
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Dclear ip nat translations *
Answer
Correct Answer: debug ip nat
Explanation
Introduction / Context:Operational visibility is critical for troubleshooting NAT. While show commands reveal current state and counters, a live, event-by-event view helps diagnose intermittent or timing-related translation issues.
Given Data / Assumptions:
- The router is performing NAT (static, dynamic, or PAT).
- You need to see translations as they are created or aged out.
- You are using Cisco IOS CLI.
Concept / Approach:IOS 'debug' commands stream real-time activity to the console or VTY (with 'terminal monitor'). For NAT, 'debug ip nat' shows creation, hits, and timeouts of translations in real time. In contrast, 'show ip nat translations' displays the present table snapshot, and 'show ip nat statistics' gives counters and pool usage, not per-packet events.
Step-by-Step Solution:
Enable logging to your session if remote: 'terminal monitor'.Run 'debug ip nat' to start live translation output.Observe creation/matches/timeouts as traffic flows.When finished, stop with 'undebug all' or 'u all' to protect CPU.Verification / Alternative check:Correlate events with pings or application traffic while watching the debug output. Confirm entries appear in 'show ip nat translations' as the debug indicates.
Why Other Options Are Wrong:show ip nat translations: Static snapshot, not live. show ip nat statistics: Summary counters only. clear ip nat translations *: Maintenance action to flush entries, not a display command.
Common Pitfalls:Running debug on busy routers can affect performance; always turn off debugging after use.
Final Answer:debug ip nat