PCNSE Deploy and Configure Firewalls Practice Question
This PCNSE practice question tests your understanding of deploy and configure firewalls. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 company needs to provide internet access to 500 internal users using a single public IP address. Which NAT method should be configured?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Source NAT with IP and port translation (PAT)
Source NAT with IP and port translation (PAT) allows 500 internal users to share a single public IP address by translating each private source IP:port combination to the public IP with a unique source port. This conserves public IPv4 addresses and is the standard method for large-scale internet access from a private network.
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.
✗
Dynamic NAT (1:1 pool)
Why it's wrong here
Dynamic NAT uses a pool of public IPs but still one-to-one, not sufficient for 500 users with one IP.
✗
Static NAT (1:1)
Why it's wrong here
Static NAT maps one internal IP to one external IP, not scalable for many users.
✗
Destination NAT
Why it's wrong here
Destination NAT is used for inbound traffic to internal servers.
✓
Source NAT with IP and port translation (PAT)
Why this is correct
PAT enables many internal IPs to share a single public IP via port multiplexing.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse Dynamic NAT (which still requires a pool of public IPs) with PAT, assuming any 'dynamic' method can share a single IP, but only PAT performs port-level multiplexing to achieve this.
Detailed technical explanation
How to think about this question
PAT, also known as NAT overload (RFC 2663), uses the transport-layer port (TCP/UDP) to multiplex multiple private hosts behind a single public IP. The firewall maintains a translation table mapping (private IP, private port) to (public IP, unique public port), and the maximum number of concurrent sessions is limited by the port range (typically 16-bit, ~65,535 ports per IP, minus reserved ports). In real-world scenarios, PAT can exhaust ports under heavy usage, requiring multiple public IPs or port range expansion.
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.
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.
Deploy and Configure Firewalls — This question tests Deploy and Configure Firewalls — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Source NAT with IP and port translation (PAT) — Source NAT with IP and port translation (PAT) allows 500 internal users to share a single public IP address by translating each private source IP:port combination to the public IP with a unique source port. This conserves public IPv4 addresses and is the standard method for large-scale internet access from a private network.
What should I do if I get this PCNSE 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.
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This PCNSE practice question is part of Courseiva's free Palo Alto Networks 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 PCNSE exam.
Question Discussion
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