JNCIP-ENT Layer 2 Authentication And Access Control Practice Question
Which TWO actions occur when an 802.1X supplicant fails authentication and a guest VLAN is configured on the EX Series switch port? (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 switch assigns the interface to the specified guest VLAN.
When authentication fails and a guest VLAN is defined, the port is moved to the guest VLAN, and standard re-authentication timers or failure actions apply.
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 switch assigns the interface to the specified guest VLAN.
Why this is correct
Correct. Failure moves the port into the guest VLAN.
- ✓
The client retains access to network resources restricted by the guest VLAN boundaries.
Why this is correct
Correct. The guest VLAN provides isolated/restricted network access.
- ✗
The switch sends a RADIUS accounting stop packet for the failed session.
Why it's wrong here
Incorrect. Accounting behavior depends on failure action, but session assignment is primary.
- ✗
The switch permanently disables the physical port until a manual reset is issued.
Why it's wrong here
Incorrect. Guest VLAN prevents port shutdown.
- ✗
The supplicant is automatically migrated to the critical authentication server group.
Why it's wrong here
Incorrect. Critical server groups are for RADIUS unreachability, not auth failure.
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.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint
This JNCIP-ENT practice question is part of Courseiva's free Juniper Networks 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 JNCIP-ENT exam.