NSE4 Authentication and VPN Practice Question
An administrator wants to allow remote users to access internal resources using a web browser without installing any client software. Which VPN type should be configured on the FortiGate?
⚠ Common exam trap
Watch out — candidates often confuse SSL VPN web mode (clientless) with SSL VPN tunnel mode (client-required), as both use SSL/TLS but differ fundamentally in whether a software client is needed for full network-layer access.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
SSL VPN web mode
SSL VPN web mode (option D) is correct because it provides clientless remote access to internal resources via a web browser, requiring no software installation. The FortiGate acts as a reverse proxy, translating HTTPS requests from the user's browser to internal HTTP/HTTPS servers, which matches the requirement for browser-only access without client software.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ZTNA access proxy
Why it's wrong here
ZTNA access proxy verifies the user and device via FortiClient EMS enrollment, then proxies traffic to specific internal applications without a full VPN tunnel. It requires the ZTNA agent to be installed and registered, and it is not a browser-only solution. Remote users would need agent enrollment, not just a web browser, so this is not the intended simple browser-based access.
- ✗
IPsec VPN with dial-up mode
Why it's wrong here
IPsec VPN in dial-up mode establishes an encrypted tunnel using IKE and requires an IPsec client, either built into the OS (e.g., Windows built-in) or third-party software. The client must be configured with pre-shared keys or certificates and the correct IPsec proposal. This is not browser-based and requires more setup than a quick web-access solution, making it unsuitable for the described scenario.
- ✗
SSL VPN tunnel mode
Why it's wrong here
SSL VPN tunnel mode gives full network-level access by creating a virtual network adapter on the client. It requires FortiClient to be installed and often includes a soak/negotiation phase where the client downloads the appropriate tunnel configuration. Although it uses SSL/TLS for transport, it still requires client software and is not restricted to browser-only access to internal web portals.
- ✓
SSL VPN web mode
Why this is correct
SSL VPN web mode provides agentless, browser-based access to internal web applications through a reverse-proxy portal. The user only needs a supported web browser and credentials, then receives a resource-list portal to reach specific HTTP/HTTPS URLs. This matches the requirement of allowing remote users to access internal web resources without installing any software or VPN client.
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.