- A
The supplicant sends an EAPOL-Start frame to begin the authentication process.
Correct because the supplicant (client) typically initiates 802.1X by sending an EAPOL-Start frame to the authenticator.
- B
The authenticator (switch) performs the actual authentication of the supplicant credentials.
Why wrong: Incorrect because the authenticator does not authenticate; it relays EAP messages between the supplicant and the RADIUS server, which performs the authentication.
- C
The authentication server (RADIUS) sends an EAP-Success message after successful validation of credentials.
Correct because the RADIUS server validates the supplicant's credentials and sends an EAP-Success (or EAP-Failure) to the authenticator, which forwards it to the supplicant.
- D
EAPOL frames are used only between the authentication server and the authenticator.
Why wrong: Incorrect because EAPOL (EAP over LAN) frames are used between the supplicant and the authenticator, not between the authenticator and the RADIUS server (which uses RADIUS protocol).
- E
The authenticator places the port in the unauthorized state before authentication completes.
Why wrong: Incorrect because the port is initially in the unauthorized state, but this is a default condition, not something the authenticator does 'before authentication completes'—the statement is ambiguous and not a key process step.
CCNP 802.1X and TrustSec Practice Question
This 350-401 practice question tests your understanding of 802.1x and trustsec. 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 two statements about 802.1X authentication process are true? (Choose two.)
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
The supplicant sends an EAPOL-Start frame to begin the authentication process.
In 802.1X, the supplicant (client) initiates the session by sending an EAPOL-Start, or the authenticator (switch) can send an EAP-Request/Identity to prompt the client. The RADIUS server is the authentication server that validates credentials and sends an EAP-Success or EAP-Failure. The authenticator does not perform the actual authentication; it only relays EAP frames.
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.
- ✓
The supplicant sends an EAPOL-Start frame to begin the authentication process.
Why this is correct
Correct because the supplicant (client) typically initiates 802.1X by sending an EAPOL-Start frame to the authenticator.
Related concept
Authentication checks who the user is.
- ✗
The authenticator (switch) performs the actual authentication of the supplicant credentials.
Why it's wrong here
Incorrect because the authenticator does not authenticate; it relays EAP messages between the supplicant and the RADIUS server, which performs the authentication.
- ✓
The authentication server (RADIUS) sends an EAP-Success message after successful validation of credentials.
Why this is correct
Correct because the RADIUS server validates the supplicant's credentials and sends an EAP-Success (or EAP-Failure) to the authenticator, which forwards it to the supplicant.
Related concept
Authentication checks who the user is.
- ✗
EAPOL frames are used only between the authentication server and the authenticator.
Why it's wrong here
Incorrect because EAPOL (EAP over LAN) frames are used between the supplicant and the authenticator, not between the authenticator and the RADIUS server (which uses RADIUS protocol).
- ✗
The authenticator places the port in the unauthorized state before authentication completes.
Why it's wrong here
Incorrect because the port is initially in the unauthorized state, but this is a default condition, not something the authenticator does 'before authentication completes'—the statement is ambiguous and not a key process step.
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 350-401 questions on access control and AAA configuration.
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FAQ
Questions learners often ask
What does this 350-401 question test?
802.1X and TrustSec — This question tests 802.1X and TrustSec — Authentication checks who the user is..
What is the correct answer to this question?
The correct answer is: The supplicant sends an EAPOL-Start frame to begin the authentication process. — In 802.1X, the supplicant (client) initiates the session by sending an EAPOL-Start, or the authenticator (switch) can send an EAP-Request/Identity to prompt the client. The RADIUS server is the authentication server that validates credentials and sends an EAP-Success or EAP-Failure. The authenticator does not perform the actual authentication; it only relays EAP frames.
What should I do if I get this 350-401 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 350-401 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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Last reviewed: Jun 18, 2026
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