JNCIP-ENT Layer 2 Authentication And Access Control Practice Question
An EX Series switch is configured with multiple-supplicant mode on an access port connected to an IP phone with a PC daisy-chained behind it. The IP phone authenticates via 802.1X, but the PC uses MAC RADIUS. The phone authenticates successfully and moves to the voice VLAN. However, when the PC boots, it fails authentication because the switch rejects a second supplicant on the same logical port index. Which configuration parameter resolves this issue?
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
✓
Configure the interface with 'set protocols dot1x interface ge-0/0/1 supplicant multiple' and ensure multi-supplicant mode is active.
In multiple-supplicant mode, you must configure 'supplicant multiple' and ensure the port is configured to support multiple clients using different authentication methods (e.g., multi-supplicant mode rather than single-supplicant).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure 'set access-profile captive-portal multiple-logins per-port'.
Why it's wrong here
Incorrect. Captive portal profiles do not manage dot1x supplicant limits.
- ✗
Set the port mode to trunk and enable voice-vlan stacking.
Why it's wrong here
Incorrect. Trunk mode alone does not bypass supplicant limits.
- ✗
Configure the interface with 'set protocols dot1x interface ge-0/0/1 mac-radius multiple-clients'.
Why it's wrong here
Incorrect. This command does not exist in Junos OS.
- ✓
Configure the interface with 'set protocols dot1x interface ge-0/0/1 supplicant multiple' and ensure multi-supplicant mode is active.
Why this is correct
Correct. Enabling multiple supplicants per port allows both the IP phone and the PC to authenticate independently.
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.