The answer is a misconfigured NAT overload pool that incorrectly assigns the inside interface Gi0/1 instead of the outside interface Gi0/0. This is the most likely cause because PAT configuration troubleshooting on the CCNA 200-301 v2 exam hinges on understanding that the overload rule must bind to an outside (WAN) interface—typically GigabitEthernet0/0—to translate internal source addresses for internet access. When the rule points to an inside interface, the router attempts to overload on a LAN-facing port, causing all translation attempts to fail, as evidenced by zero hits and thousands of misses in the show ip nat statistics output. This scenario tests your ability to read dynamic mapping entries and differentiate inside from outside interfaces, a common trap where candidates confuse the interface where traffic originates with the one where translation occurs. A reliable memory tip: PAT overload always needs an outside interface—think “out to the internet, not in to the LAN.”
CCNA Network Services and Security Practice Question
This 200-301 practice question tests your understanding of network services and security. 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.
Refer to the exhibit. An administrator has configured PAT for internal hosts to access the internet, but users report that they cannot reach external websites. The administrator suspects a NAT issue and runs the show ip nat statistics command. What is the most likely cause of the problem?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The NAT overload pool is incorrectly configured with the inside interface Gi0/1 instead of the outside interface Gi0/0.
The dynamic mapping line explicitly shows 'interface GigabitEthernet0/1', which is an inside interface according to the output. Overload must be tied to the outside interface.
B
The access-list 1 used in the NAT statement is not matching any traffic.
Why wrong: While an incorrect ACL can cause misses, the exhibit's dynamic mapping clearly shows the interface mismatch as the definitive cause.
C
CEF switching is disabled, causing all packets to be punted to the process level and NAT to fail.
Why wrong: The output shows CEF Punted packets equal to the misses, but CEF is not disabled; the root cause is the incorrect interface binding.
D
The maximum number of NAT translations has been reached, causing new translations to be denied.
Why wrong: Active translations are 0, and there is no indication of a limit being hit. The misses are due to the misconfigured interface, not table exhaustion.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The NAT overload pool is incorrectly configured with the inside interface Gi0/1 instead of the outside interface Gi0/0.
The Dynamic mappings section reveals an inside source overload entry bound to interface GigabitEthernet0/1, which is listed under Inside interfaces. For PAT to work, the overload rule must use an outside (WAN) interface (here GigabitEthernet0/0), not an inside interface. This misconfiguration causes all translation attempts to fail, reflected in Hits: 0 and Misses: 15042.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The NAT overload pool is incorrectly configured with the inside interface Gi0/1 instead of the outside interface Gi0/0.
Why this is correct
The dynamic mapping line explicitly shows 'interface GigabitEthernet0/1', which is an inside interface according to the output. Overload must be tied to the outside interface.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The access-list 1 used in the NAT statement is not matching any traffic.
Why it's wrong here
While an incorrect ACL can cause misses, the exhibit's dynamic mapping clearly shows the interface mismatch as the definitive cause.
✗
CEF switching is disabled, causing all packets to be punted to the process level and NAT to fail.
Why it's wrong here
The output shows CEF Punted packets equal to the misses, but CEF is not disabled; the root cause is the incorrect interface binding.
✗
The maximum number of NAT translations has been reached, causing new translations to be denied.
Why it's wrong here
Active translations are 0, and there is no indication of a limit being hit. The misses are due to the misconfigured interface, not table exhaustion.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The NAT overload pool is incorrectly configured with the inside interface Gi0/1 instead of the outside interface Gi0/0.Correct answer▾
Why this is correct
The dynamic mapping line explicitly shows 'interface GigabitEthernet0/1', which is an inside interface according to the output. Overload must be tied to the outside interface.
✗The access-list 1 used in the NAT statement is not matching any traffic.Wrong answer — click to see why▾
Why this is wrong here
Candidates may focus on Hits: 0 and Misses: 15042 as typical of an ACL issue, but the explicit interface binding in the dynamic mapping is the direct evidence of misconfiguration.
✗CEF switching is disabled, causing all packets to be punted to the process level and NAT to fail.Wrong answer — click to see why▾
Why this is wrong here
The high CEF Punted count mirrors the misses, leading some to believe CEF is the problem, but the exhibit does not indicate CEF is disabled.
✗The maximum number of NAT translations has been reached, causing new translations to be denied.Wrong answer — click to see why▾
Why this is wrong here
Candidates might assume that a high miss count reflects a full translation table, but the total active translations show 0.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Trap categories for this question
Command / output trap
While an incorrect ACL can cause misses, the exhibit's dynamic mapping clearly shows the interface mismatch as the definitive cause.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 200-301 NAT questions on configuration and troubleshooting.
Network Services and Security — This question tests Network Services and Security — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The NAT overload pool is incorrectly configured with the inside interface Gi0/1 instead of the outside interface Gi0/0. — The Dynamic mappings section reveals an inside source overload entry bound to interface GigabitEthernet0/1, which is listed under Inside interfaces. For PAT to work, the overload rule must use an outside (WAN) interface (here GigabitEthernet0/0), not an inside interface. This misconfiguration causes all translation attempts to fail, reflected in Hits: 0 and Misses: 15042.
What should I do if I get this 200-301 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 200-301 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Exhibit: Users report no internet access after PAT was configured. The inside and outside interfaces are marked correctly. Which missing configuration is the most likely cause?
Why A: PAT needs both the inside and outside interface roles and a NAT statement referencing an ACL that identifies the inside local addresses. Without the ACL match and NAT overload rule, translation does not occur for user traffic.
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.
This 200-301 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 200-301 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.