The answer is that the router is using both static NAT and PAT simultaneously. This conclusion is drawn directly from the NAT translation table output, which shows two distinct translation types: the first two entries include protocol (udp, tcp) and port numbers (1234, 5678), indicating dynamic PAT where multiple inside local addresses share a single inside global address through port multiplexing, while the third entry has no protocol or port, with a simple one-to-one mapping from 10.0.0.21 to 192.0.2.21, which is the hallmark of a static NAT configuration. On the ENCOR 350-401 exam, this question tests your ability to read and interpret the show ip nat translations output, a common troubleshooting skill, and often appears as a trap where candidates mistakenly think all entries are PAT because they see ports, missing the static entry. A key memory tip: if you see a protocol and port in the first column, it is PAT; if you see three dashes, it is static or dynamic NAT without overload.
CCNP NAT and DHCP Practice Question
This 350-401 practice question tests your understanding of nat and dhcp. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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 on Router R9:
R9# show ip nat translations
Pro Inside global Inside local Outside local Outside global
udp 192.0.2.20:1234 10.0.0.20:1234 203.0.113.1:53 203.0.113.1:53
tcp 192.0.2.20:5678 10.0.0.20:5678 198.51.100.1:80 198.51.100.1:80
--- 192.0.2.21 10.0.0.21 --- ---
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The router is using both static NAT and PAT simultaneously.
The output shows a mix of dynamic PAT translations (with ports) and a static NAT entry (no protocol/port). The static entry maps 10.0.0.21 to 192.0.2.21, while PAT is used for 10.0.0.20.
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.
✗
All translations are dynamic.
Why it's wrong here
The third entry has no protocol, indicating it is static.
✓
The router is using both static NAT and PAT simultaneously.
Why this is correct
Static NAT for 10.0.0.21 and PAT for 10.0.0.20 are both active.
Related concept
Static NAT maps one inside address to one outside address.
✗
The router is configured with a single NAT pool.
Why it's wrong here
Static NAT does not use a pool; PAT may use a pool or interface.
✗
The inside global address 192.0.2.20 is used for both static and dynamic translations.
Why it's wrong here
192.0.2.20 is used only for dynamic PAT; static uses 192.0.2.21.
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.
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.
What to study next
Got this wrong? Here's your next step.
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 350-401 NAT questions on configuration and troubleshooting.
NAT and DHCP — This question tests NAT and DHCP — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The router is using both static NAT and PAT simultaneously. — The output shows a mix of dynamic PAT translations (with ports) and a static NAT entry (no protocol/port). The static entry maps 10.0.0.21 to 192.0.2.21, while PAT is used for 10.0.0.20.
What should I do if I get this 350-401 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 350-401 NAT questions on configuration and troubleshooting.
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. A network engineer runs the following command on Router R5:
R5# show ip nat translations
Pro Inside global Inside local Outside local Outside global
udp 192.0.2.20:1234 10.0.0.20:1234 203.0.113.1:53 203.0.113.1:53
tcp 192.0.2.20:5678 10.0.0.20:5678 198.51.100.1:80 198.51.100.1:80
Based on this output, what can be concluded?
hard
A.The router is configured with static NAT for two internal hosts.
✓ B.The router is performing Port Address Translation (PAT) for multiple sessions from the same internal host.
C.The router is performing destination NAT.
D.The inside local address 10.0.0.20 is using two different global addresses.
Why B: The output shows two translations using the same inside global address (192.0.2.20) but different ports, which is characteristic of PAT. One translation is UDP (DNS) and one is TCP (HTTP).
Last reviewed: Jun 18, 2026
Question Discussion
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