- A
NAT is working correctly; the asterisk indicates a packet that was translated and fast-switched.
The asterisk shows fast-switching, and translations are occurring bidirectionally.
- B
NAT is failing; the asterisk indicates a packet that was dropped.
Why wrong: The asterisk does not indicate a drop; it indicates fast-switching.
- C
NAT is working but only for outbound traffic; return traffic is not being translated.
Why wrong: Return traffic is being translated, as seen in line 4.
- D
NAT is not configured; the output shows only routing information.
Why wrong: The output clearly shows NAT translations.
Question 142 of 2,152
Debug IP NAT Detailed
This 300-410 practice question tests your understanding of nat and pat. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer runs the following command to troubleshoot a NAT issue:
R1# debug ip nat detailed
NAT: s=10.1.1.1->10.2.2.2, d=192.168.1.1 [45] NAT: s=10.1.1.1->10.2.2.2, d=192.168.1.1 [46] NAT: s=10.1.1.1->10.2.2.2, d=192.168.1.1 [47] NAT*: s=192.168.1.1, d=10.2.2.2->10.1.1.1 [48] NAT: s=10.1.1.1->10.2.2.2, d=192.168.1.1 [49]
What does this output indicate?
Quick Answer
The correct interpretation is that NAT is working correctly, with the asterisk indicating a packet that was translated and fast-switched. This output from the debug ip nat detailed command shows successful translation of source address 10.1.1.1 to 10.2.2.2 for outbound traffic, and the reverse translation for return traffic. The asterisk on line [48] is the key detail—it signifies that this particular packet was processed by Cisco Express Forwarding (CEF) fast-switching rather than process-switched, which is normal and expected behavior for established NAT sessions. On the Cisco CCNP ENARSI 300-410 exam, this question tests your ability to distinguish between normal NAT operation and error conditions, as many candidates mistakenly interpret the asterisk as a sign of failure or corruption. A common trap is confusing the asterisk with a NAT overload entry or assuming it indicates a dropped packet. Memory tip: think of the asterisk as a “star” for “switched”—it marks the packet that took the fast path through the hardware.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
NAT is working correctly; the asterisk indicates a packet that was translated and fast-switched.
The output shows successful NAT translations: the source IP 10.1.1.1 is translated to 10.2.2.2 for outbound packets (lines without asterisk), and the return packet from 192.168.1.1 has its destination translated back to 10.1.1.1 (line with asterisk). The asterisk in 'NAT*' indicates that the packet was both translated and fast-switched (process-switched packets lack the asterisk), confirming correct operation.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
NAT is working correctly; the asterisk indicates a packet that was translated and fast-switched.
Why this is correct
The asterisk shows fast-switching, and translations are occurring bidirectionally.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
NAT is failing; the asterisk indicates a packet that was dropped.
Why it's wrong here
The asterisk does not indicate a drop; it indicates fast-switching.
- ✗
NAT is working but only for outbound traffic; return traffic is not being translated.
Why it's wrong here
Return traffic is being translated, as seen in line 4.
- ✗
NAT is not configured; the output shows only routing information.
Why it's wrong here
The output clearly shows NAT translations.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that the asterisk in NAT debug output indicates a problem or drop, when in fact it confirms fast-switched translation and successful bidirectional NAT operation.
Trap categories for this question
Command / output trap
The output clearly shows NAT translations.
Detailed technical explanation
How to think about this question
The asterisk in 'debug ip nat' output signifies that the packet was fast-switched using Cisco Express Forwarding (CEF) or another fast-switching path, meaning it bypassed the process-switched path for efficiency. In contrast, packets without an asterisk are process-switched, which occurs for the first packet in a flow or when CEF is disabled. This distinction is critical for troubleshooting performance issues in high-throughput NAT environments.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Visual reference
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
NAT and PAT — study guide chapter
Learn the concepts, then practise the questions
- →
NAT and PAT practice questions
Targeted practice on this topic area only
- →
All 300-410 questions
2,152 questions across all exam domains
- →
Cisco CCNP ENARSI 300-410 study guide
Full concept coverage aligned to exam objectives
- →
300-410 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related 300-410 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Layer 3 Technologies practice questions
Practise 300-410 questions linked to Layer 3 Technologies.
EIGRP Troubleshooting practice questions
Practise 300-410 questions linked to EIGRP Troubleshooting.
OSPF Troubleshooting (v2/v3) practice questions
Practise 300-410 questions linked to OSPF Troubleshooting (v2/v3).
BGP Troubleshooting practice questions
Practise 300-410 questions linked to BGP Troubleshooting.
Route Redistribution practice questions
Practise 300-410 questions linked to Route Redistribution.
Policy-Based Routing (PBR) practice questions
Practise 300-410 questions linked to Policy-Based Routing (PBR).
VRF-Lite practice questions
Practise 300-410 questions linked to VRF-Lite.
Route Maps and Route Filtering practice questions
Practise 300-410 questions linked to Route Maps and Route Filtering.
Administrative Distance practice questions
Practise 300-410 questions linked to Administrative Distance.
Route Summarization practice questions
Practise 300-410 questions linked to Route Summarization.
Bidirectional Forwarding Detection (BFD) practice questions
Practise 300-410 questions linked to Bidirectional Forwarding Detection (BFD).
VPN Technologies practice questions
Practise 300-410 questions linked to VPN Technologies.
Practice this exam
Start a free 300-410 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this 300-410 question test?
NAT and PAT — This question tests NAT and PAT — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: NAT is working correctly; the asterisk indicates a packet that was translated and fast-switched. — The output shows successful NAT translations: the source IP 10.1.1.1 is translated to 10.2.2.2 for outbound packets (lines without asterisk), and the return packet from 192.168.1.1 has its destination translated back to 10.1.1.1 (line with asterisk). The asterisk in 'NAT*' indicates that the packet was both translated and fast-switched (process-switched packets lack the asterisk), confirming correct operation.
What should I do if I get this 300-410 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More 300-410 practice questions
- Drag and drop the steps to negotiate an IKEv2 IPsec site-to-site tunnel into the correct order, from first to last.
- Drag and drop the steps to troubleshoot an IPsec site-to-site VPN adjacency failure into the correct order, from first t…
- Drag and drop the steps to verify and validate the operational state of an IPsec site-to-site VPN into the correct order…
- Consider the following configuration snippet: ip cef ! interface GigabitEthernet0/0 ip address 10.0.0.1 255.255.255.25…
- A router is configured with 'logging host 10.1.1.100' and 'logging trap informational'. The engineer notices that syslog…
- Drag and drop the steps to configure a GRE tunnel for IPv6 over IPv4 into the correct order, from first to last.
Last reviewed: Jul 4, 2026
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.