The answer is to enable split tunneling in the SSL VPN portal configuration, add the DNS server subnet (10.0.1.10/32) to the split tunneling destination list, and create a firewall policy that permits the encrypted traffic. This works because split tunneling allows the FortiGate to selectively route only specified subnets—like the corporate DNS server—through the encrypted tunnel, while all other traffic bypasses the VPN and goes directly to the internet. On the Fortinet NSE 4 exam, this scenario tests your understanding of SSL VPN tunnel mode and the interplay between portal settings and policy routing; a common trap is forgetting that the DNS server’s subnet must be explicitly listed in the split tunneling destinations, or assuming that enabling split tunneling alone is sufficient without a matching firewall policy. Remember the three-step mnemonic: “Portal, List, Policy”—enable split tunneling in the portal, add the DNS subnet to the list, and allow it with a policy.
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 FortiGate is configured for SSL VPN tunnel mode with split tunneling enabled. The administrator wants to ensure that traffic to the corporate DNS server (10.0.1.10) goes through the tunnel while all other traffic goes directly to the internet. Which THREE configuration steps are required?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add the DNS server subnet (10.0.1.0/24) to the split tunneling destinations
For split tunneling with specific destinations routed through the VPN, the administrator must configure the SSL VPN settings to include the DNS server subnet in the split tunneling list, enable split tunneling, and ensure the firewall policy allows the 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.
✓
Add the DNS server subnet (10.0.1.0/24) to the split tunneling destinations
Why this is correct
This ensures traffic to that subnet is sent through the tunnel.
Configure a static route on the client for 10.0.1.0/24 via the virtual adapter
Why it's wrong here
The FortiGate pushes routes; the client does not need manual static routes.
Common exam traps
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 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 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: Add the DNS server subnet (10.0.1.0/24) to the split tunneling destinations — For split tunneling with specific destinations routed through the VPN, the administrator must configure the SSL VPN settings to include the DNS server subnet in the split tunneling list, enable split tunneling, and ensure the firewall policy allows the 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.
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Question Discussion
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