The correct answer is a Virtual IP (VIP) mapping 203.0.113.10:443 to 192.168.1.10:443, combined with a firewall policy that permits the traffic and does not perform source NAT. This configuration preserves the original source IP because the VIP only translates the destination address, while the absence of SNAT ensures the client’s real IP is forwarded to the internal server. On the Fortinet NSE 4 exam, this scenario tests your understanding of how inbound HTTPS traffic flows through a FortiGate without hiding the client address—a common requirement for logging or access control. A frequent trap is assuming a standard static NAT or enabling SNAT on the inbound policy, which would replace the source IP with the FortiGate’s interface IP. To remember: VIP for destination, no SNAT for source—think “VIP in, source out.”
NSE4 Firewall Policies and NAT Practice Question
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 company needs to allow inbound HTTPS traffic from the internet to a web server behind the FortiGate. The public IP is 203.0.113.10, and the internal server is 192.168.1.10. The server must receive the original source IP of the client. Which THREE configurations are required to achieve this?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A firewall policy from WAN to DMZ allowing HTTPS traffic to the VIP
To allow inbound HTTPS and preserve the source IP, you need a VIP to translate destination, a firewall policy allowing the traffic, and no source NAT (or use a policy that does not SNAT). SNAT would hide the original source IP.
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.
✓
A firewall policy from WAN to DMZ allowing HTTPS traffic to the VIP
Why this is correct
The policy must permit the traffic to the VIP destination.
Related concept
Static NAT maps one inside address to one outside address.
✓
Disabling source NAT on the firewall policy (set nat enable disable)
Why this is correct
Disabling SNAT ensures the original source IP is preserved.
Related concept
Static NAT maps one inside address to one outside address.
✗
A static route for 203.0.113.10 pointing to the ISP gateway
Why it's wrong here
The VIP handles the IP mapping; routing for the public IP is required but typically done via default route.
✗
A Central SNAT policy to translate the source to the FortiGate's IP
Why it's wrong here
This would hide the original source IP, which is not desired.
✓
A Virtual IP (VIP) mapping 203.0.113.10:443 to 192.168.1.10:443
Why this is correct
VIP performs DNAT for inbound traffic.
Related concept
Static NAT maps one inside address to one outside address.
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 NSE4 NAT questions on configuration and troubleshooting.
Firewall Policies and NAT — This question tests Firewall Policies and NAT — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: A firewall policy from WAN to DMZ allowing HTTPS traffic to the VIP — To allow inbound HTTPS and preserve the source IP, you need a VIP to translate destination, a firewall policy allowing the traffic, and no source NAT (or use a policy that does not SNAT). SNAT would hide the original source IP.
What should I do if I get this NSE4 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 NSE4 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 →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.