easyMultiple Choice
300-410 Practice Question: Runs the following command on Router R1: R1# show…
A network engineer runs the following command on Router R1:
R1# show ip nat translations
Pro Inside global Inside local Outside local Outside global udp 192.0.2.10:10000 10.0.0.10:10000 203.0.113.5:53 203.0.113.5:53 udp 192.0.2.10:10001 10.0.0.11:10000 203.0.113.5:53 203.0.113.5:53 udp 192.0.2.10:10002 10.0.0.12:10000 203.0.113.5:53 203.0.113.5:53
R1# show ip nat statistics
Total active translations: 3 (0 static, 3 dynamic; 3 extended) Outside interfaces: GigabitEthernet0/1 Inside interfaces: GigabitEthernet0/0 Hits: 150 Misses: 0 CEF Translated packets: 150, CEF Punted packets: 0 Expired translations: 0 Dynamic mappings: -- Inside Source
[Id] ip nat inside source list ACL1 interface GigabitEthernet0/1 overload
refcount 3
Based on this output, which statement is correct?
⚠ Common exam trap
Cisco often tests the distinction between PAT (overload) and basic NAT (pool without overload), and candidates may mistakenly think that multiple translations to the same destination (203.0.113.5:53) indicate a pool exhaustion or static NAT, when in fact the unique source ports confirm PAT is functioning correctly.
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
✓
PAT is working correctly; multiple inside hosts share the same global address with unique ports.
The output shows three dynamic NAT translations, all using the same inside global address 192.0.2.10 with unique source ports (10000, 10001, 10002). This is the hallmark of Port Address Translation (PAT) or NAT overload, where multiple inside hosts (10.0.0.10, 10.0.0.11, 10.0.0.12) share a single public IP address by differentiating sessions via layer-4 port numbers. The 'overload' keyword in the dynamic mapping confirms PAT is active and working correctly.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
PAT is working correctly; multiple inside hosts share the same global address with unique ports.
Why this is correct
Unique source ports (10000–10002) map three inside locals onto one global address, confirming PAT overload. The `overload` keyword on the inside source list, combined with three extended dynamic translations, satisfies the requirement that multiple hosts share 192.0.2.10. Distinct port allocation, not address pooling, is the mechanism.
- ✗
The NAT pool is exhausted because all addresses are used.
Why it's wrong here
The configuration uses interface overload, which multiplexes many inside hosts onto one global address using port numbers, so no pool exists to exhaust. It tempts because three translations share 192.0.2.10, but exhaustion applies to finite address pools, not PAT.
- ✗
Static NAT is configured for DNS traffic.
Why it's wrong here
The statistics line reports 0 static and 3 dynamic translations, and the mapping is ip nat inside source list overload, so no static entry exists. It tempts because the outside entries are port 53 DNS servers, but those are destinations, not static NAT statements.
- ✗
The inside and outside interfaces are swapped.
Why it's wrong here
GigabitEthernet0/1 is correctly listed as outside and GigabitEthernet0/0 as inside, matching the overload mapping direction. It tempts because the inside local addresses differ from the single global address, which looks reversed, but PAT translation normally rewrites source addresses this way.
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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.