The answer is a firewall policy allowing traffic between the VPN interfaces, along with proper Phase 2 selectors and routes on the hub FortiGate. In a hub-and-spoke IPsec VPN, the hub must have routes to both spoke subnets and Phase 2 selectors that define the traffic between those spokes; without these, the hub cannot forward the encrypted packets. The firewall policy is the final gatekeeper—it must explicitly permit inter-spoke traffic on the VPN interfaces, or the packets will be dropped even if routing and encryption are correct. On the Fortinet NSE 4 exam, this question tests your understanding that the hub acts as a routing and policy intermediary, not just a tunnel endpoint. A common trap is thinking only Phase 2 selectors are needed, but the firewall policy is equally mandatory. Memory tip: think “Routes, Selectors, Policy”—the three pillars of spoke-to-spoke direct communication.
NSE4 Authentication and VPN Practice Question
This NSE4 practice question tests your understanding of authentication and vpn. 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 has multiple branch offices connected via IPsec VPN in a hub-and-spoke topology. They want to enable direct communication between branch offices without routing traffic through the hub. Which THREE configurations are required on the hub FortiGate? (Choose three.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Static routes for each branch's subnet pointing to the respective VPN interface
To allow spoke-to-spoke communication without hub, the hub must have routes to both spokes, Phase 2 selectors to allow traffic between spokes, and a firewall policy permitting inter-spoke traffic.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Enable 'forward traffic' in Phase 1 settings
Why it's wrong here
There is no such setting; traffic forwarding is controlled by policies and routing.
✓
Static routes for each branch's subnet pointing to the respective VPN interface
Why this is correct
The hub needs routes to forward traffic between spokes.
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related NSE4 subnetting questions on CIDR, address ranges, and subnet selection.
Authentication and VPN — This question tests Authentication and VPN — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Static routes for each branch's subnet pointing to the respective VPN interface — To allow spoke-to-spoke communication without hub, the hub must have routes to both spokes, Phase 2 selectors to allow traffic between spokes, and a firewall policy permitting inter-spoke traffic.
What should I do if I get this NSE4 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related NSE4 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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. In a hub-and-spoke IPsec VPN topology with FortiGate, the spoke sites cannot communicate directly with each other. What configuration change allows direct spoke-to-spoke communication?
medium
A.Set the 'add-route' option to 'enable' on the spoke Phase 1 settings
✓ B.Configure dynamic routing (BGP) on all sites and enable route exchange
C.Add static routes on the hub pointing to each spoke's subnet via the respective tunnels
D.Create a separate IPsec VPN between each spoke pair
Why B: By default, hub-and-spoke only allows communication between spokes via the hub. To enable direct spoke-to-spoke, you need to add Phase 2 selectors with each other's subnets on the hub or configure dynamic routing (BGP/OSPF) to advertise routes between spokes. Another method is to use ADVPN (Auto Discovery VPN).
Last reviewed: Jun 21, 2026
Question Discussion
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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.
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