The answer is to verify that the firewall policy between the SSL VPN interface and the internal network allows the traffic. Even when an SSL VPN policy correctly permits access to a specific internal subnet, that policy only governs authentication and tunnel assignment; the actual packet forwarding still requires a separate firewall policy on the FortiGate to permit traffic from the SSL VPN interface (typically ssl.root) to the destination internal network. This is a classic two-policy requirement on FortiOS, and the Fortinet NSE 4 exam frequently tests this distinction to catch candidates who assume the SSL VPN policy alone is sufficient. A common trap is overlooking the firewall policy when users are connected but cannot access internal resources, as the connection succeeds at the VPN layer but packets are silently dropped at the security policy layer. Memory tip: think of the SSL VPN policy as the "door key" and the firewall policy as the "hall pass"—both are required to reach the internal network.
NSE4 Authentication and VPN Practice Question
This NSE4 practice question tests your understanding of authentication and vpn. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 is troubleshooting an SSL VPN connection issue. Users can connect but cannot access internal resources. The administrator checks the SSL VPN policy and confirms it allows access to the internal subnet. What should the administrator check next?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Verify that the firewall policy between the SSL VPN interface and the internal network allows the traffic
Even if the SSLVPN policy is correct, the traffic must also be permitted by the firewall policies between the SSL VPN interface and the internal network. A common mistake is not having a firewall policy that allows traffic from the SSL VPN interface (e.g., ssl.root) to the internal network.
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.
✓
Verify that the firewall policy between the SSL VPN interface and the internal network allows the traffic
Why this is correct
Correct. The firewall policy must explicitly permit traffic from the SSLVPN zone to the internal zone.
Check the routing table on the FortiGate for the internal subnet
Why it's wrong here
Routing is usually correct if the policy allows; routing issues would affect all traffic.
✗
Ensure the users have the correct client software installed
Why it's wrong here
Client software is needed for tunnel mode, but the issue seems to be connectivity after tunnel is up.
✗
Check the FortiGate's DNS settings
Why it's wrong here
DNS is not directly related to traffic forwarding.
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 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: Verify that the firewall policy between the SSL VPN interface and the internal network allows the traffic — Even if the SSL VPN policy is correct, the traffic must also be permitted by the firewall policies between the SSL VPN interface and the internal network. A common mistake is not having a firewall policy that allows traffic from the SSL VPN interface (e.g., ssl.root) to the internal network.
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
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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. A FortiGate administrator is troubleshooting an SSL VPN issue where remote users cannot access internal resources after successful authentication. Which TWO steps should the admin take to resolve the issue? (Select two.)
medium
✓ A.Verify that a firewall policy exists allowing traffic from the SSL VPN interface to the internal network
B.Increase the authentication timeout
✓ C.Check the routing table on the FortiGate to ensure return routes are present
D.Restart the FortiGate
E.Disable the SSL VPN portal
Why A: If authentication succeeds but traffic fails, likely causes are missing firewall policy or incorrect routing. Check firewall policies for SSL VPN interface and ensure appropriate routes (e.g., enable split tunneling or add static routes).
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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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