The answer is LDAP authentication. This method allows the FortiGate to authenticate users against an Active Directory domain without storing domain credentials locally because the FortiGate acts as an LDAP client, forwarding the username and password directly to the domain controller for verification via the LDAP protocol. The domain controller processes the credentials and returns only an accept or reject response, so the FortiGate never caches or stores the actual password. On the Fortinet NSE 4 Network Security Professional NSE4 exam, this question tests your understanding of how LDAP differs from local user authentication—a common trap is confusing LDAP with RADIUS or thinking the FortiGate must store a copy of the password for offline validation. Remember: LDAP is a “pass-through” protocol; the FortiGate simply relays the credentials to the directory server. A helpful memory tip is “LDAP = Lookup, Don’t Archive Passwords.”
NSE4 Authentication and VPN Practice Question
This NSE4 practice question tests your understanding of authentication and vpn. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Which authentication method allows FortiGate to authenticate users against an Active Directory domain without storing domain credentials locally?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
LDAP authentication
LDAP authentication requires the FortiGate to contact the domain controller using the LDAP protocol, verifying credentials without storing them locally. Local users store credentials on the FortiGate itself.
Key principle: Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
FSSO polling
Why it's wrong here
FSSO polls AD for user login events but does not perform authentication directly.
✗
RADIUS authentication
Why it's wrong here
RADIUS can authenticate against AD, but it typically uses a separate RADIUS server, not direct LDAP.
✓
LDAP authentication
Why this is correct
LDAP allows FortiGate to query the AD server for authentication without local storage.
Related concept
Authentication checks who the user is.
✗
Local user database
Why it's wrong here
Local users store credentials on the FortiGate, not leveraging AD remotely.
Common exam traps
Common exam trap: authentication is not authorization
Logging in proves the user can authenticate. It does not automatically mean the user is allowed to enter privileged or configuration mode. Watch for AAA authorization, privilege level and command authorization details.
Detailed technical explanation
How to think about this question
This kind of question is testing the difference between identity and permission. A user may successfully log in to a router because authentication is working, but still fail to enter configuration mode because authorization is missing, misconfigured or mapped to a lower privilege level.
KKey Concepts to Remember
Authentication checks who the user is.
Authorization controls what the user is allowed to do after login.
Privilege levels affect access to EXEC and configuration commands.
AAA, TACACS+ and RADIUS can separate login success from command access.
TExam Day Tips
→Do not assume successful login means full administrative access.
→Look for words such as cannot enter configuration mode, privilege level, authorization or command access.
→Separate login problems from permission problems before choosing the answer.
Key takeaway
Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
Real-world example
How this comes up in practice
A junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
What to study next
Got this wrong? Here's your next step.
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related NSE4 questions on access control and AAA configuration.
Authentication and VPN — This question tests Authentication and VPN — Authentication checks who the user is..
What is the correct answer to this question?
The correct answer is: LDAP authentication — LDAP authentication requires the FortiGate to contact the domain controller using the LDAP protocol, verifying credentials without storing them locally. Local users store credentials on the FortiGate itself.
What should I do if I get this NSE4 question wrong?
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related NSE4 questions on access control and AAA configuration.
What is the key concept behind this question?
Authentication checks who the user is.
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Question Discussion
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