mediumMultiple SelectObjective-mapped
350-701 Practice Question: Is troubleshooting 802.1X authentication failures
A network engineer is troubleshooting 802.1X authentication failures. Which two components are required for a successful 802.1X authentication? (Choose two.)
⚠ Common exam trap
Cisco often tests that candidates mistakenly include supporting infrastructure (DHCP, DNS) as required components, but 802.1X authentication is purely Layer 2 and does not depend on IP-based services until after successful authentication.
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
✓
Authentication server (ISE)
In 802.1X authentication, the supplicant (client software) initiates the authentication process by sending an EAPOL-Start message, and the authentication server (ISE) validates the client's credentials via RADIUS. Without both, the authentication cannot complete. The supplicant provides identity, while the authentication server makes the final permit/deny decision.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DHCP server
Why it's wrong here
DHCP server provides IP addresses after authentication, not required for authentication itself.
- ✓
Authentication server (ISE)
Why this is correct
ISE validates credentials and grants access.
- ✓
Supplicant (client software)
Why this is correct
The supplicant initiates authentication on the endpoint.
- ✗
DNS server
Why it's wrong here
DNS is not required for 802.1X authentication.
- ✗
RADIUS proxy
Why it's wrong here
A RADIUS proxy is optional, not required for basic 802.1X.
Visual reference
Quick reference
AAA Protocol Comparison
| Protocol | Port(s) | Encryption | Transport | Primary Use |
|---|---|---|---|---|
| RADIUS | 1812 / 1813 | Password only | UDP | Network access control |
| TACACS+ | 49 | Full packet | TCP | Device administration |
| Diameter | 3868 | Full session | TCP / SCTP | Carrier / mobile networks |
| 802.1X | — | EAP-based | Layer 2 | Port-based access control |
TACACS+ encrypts the entire packet; RADIUS only encrypts the password field — a key exam distinction.
Go deeper
Related to this question
About these practice questions
One of 978 original 350-701 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-701 practice question is part of Courseiva's free Cisco 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 350-701 exam.