hardMultiple ChoiceObjective-mapped
300-410 Practice Question: Router R1 is configured with ip nat inside source…
Router R1 is configured with ip nat inside source list 100 interface GigabitEthernet0/1 overload. Users report that some websites load slowly or partially. Router R1 shows: show ip nat statistics: Total active translations: 65535 (0 static, 65535 dynamic; 65535 extended). The NAT pool is exhausted. What is the root cause?
⚠ Common exam trap
Cisco often tests the misconception that adding more public IPs or clearing the NAT table is the primary fix, when in reality the root cause is port exhaustion due to long default timeouts, and the proper solution is to adjust timer values to reclaim ports faster.
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
✓
Reduce the NAT timeout values using ip nat translation timeout and ip nat translation tcp-timeout.
The NAT pool is exhausted with 65535 active translations, which is the maximum number of PAT entries (port numbers) available for a single public IP. This causes new or existing sessions to fail or load partially. Reducing NAT timeout values (e.g., ip nat translation timeout and ip nat translation tcp-timeout) frees port mappings faster, alleviating the exhaustion without requiring additional public IPs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Reduce the NAT timeout values using ip nat translation timeout and ip nat translation tcp-timeout.
Why this is correct
Shorter timeouts free up entries faster, preventing exhaustion.
- ✗
Increase the access-list 100 to include more internal hosts.
Why it's wrong here
This would increase the number of translations, worsening the problem.
- ✗
Change the NAT to use a pool of public IPs instead of overload.
Why it's wrong here
Using a pool would allow more translations but requires multiple public IPs and is not a direct fix for the timeout issue.
- ✗
Clear the NAT table with clear ip nat translation * periodically.
Why it's wrong here
This is a temporary workaround, not a root cause fix.
Visual reference
Go deeper
Related to this question
About these practice questions
This 300-410 question is part of Courseiva's 1,966-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.