This NSE4 practice question tests your understanding of firewall policies and nat. 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 FortiGate administrator configures a Central SNAT policy to translate internal IPs to a single public IP for internet access. However, traffic from a specific internal server (10.0.1.100) must use a different public IP. The administrator also creates a policy-based NAT rule in the firewall policy for that server. Which NAT method takes precedence?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Central SNAT takes precedence over policy-based NAT
In FortiGate, when both Central SNAT and policy-based NAT (configured within a firewall policy) are present, Central SNAT takes precedence. This is because Central SNAT is evaluated before policy-based NAT in the NAT processing order, and once a match is found in Central SNAT, the system applies it and does not proceed to policy-based NAT. The specific server's traffic (10.0.1.100) would still be subject to the Central SNAT rule unless a more specific Central SNAT rule is created for that IP.
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.
✓
Central SNAT takes precedence over policy-based NAT
Why this is correct
Central SNAT overrides policy-based NAT when both exist.
Related concept
Read the scenario before looking for a memorised answer.
✗
Policy-based NAT takes precedence because it is more specific
Why it's wrong here
Central SNAT takes precedence over policy-based NAT.
✗
Central SNAT takes precedence because it is evaluated after policy-based NAT
Why it's wrong here
Central SNAT is evaluated first and takes precedence.
✗
The most recently created rule takes precedence
Why it's wrong here
Order is not based on creation time.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume policy-based NAT is more specific and thus takes precedence, but FortiGate's NAT evaluation order is fixed and Central SNAT always overrides policy-based NAT regardless of specificity.
Detailed technical explanation
How to think about this question
Under the hood, FortiGate's NAT processing follows a deterministic sequence: first Central SNAT (if enabled), then policy-based NAT (configured in the firewall policy's NAT section), and finally VIP/load balancing. This order is hardcoded and cannot be changed. In a real-world scenario, if an administrator needs a specific server to use a different public IP, they must create a more specific Central SNAT rule (e.g., with a source address of 10.0.1.100) that matches before the broader rule, rather than relying on policy-based NAT.
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.
Firewall Policies and NAT — This question tests Firewall Policies and NAT — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Central SNAT takes precedence over policy-based NAT — In FortiGate, when both Central SNAT and policy-based NAT (configured within a firewall policy) are present, Central SNAT takes precedence. This is because Central SNAT is evaluated before policy-based NAT in the NAT processing order, and once a match is found in Central SNAT, the system applies it and does not proceed to policy-based NAT. The specific server's traffic (10.0.1.100) would still be subject to the Central SNAT rule unless a more specific Central SNAT rule is created for that IP.
What should I do if I get this NSE4 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 NSE4 practice question is part of Courseiva's free Fortinet 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 NSE4 exam.
Question Discussion
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