JNCIS-ENT Layer 2 Switching And VLANs Practice Question
An administrator needs to restrict MAC learning on a specific access port (ge-0/0/5) on an EX Series switch to a maximum of 2 learned MAC addresses to prevent MAC flooding attacks. Where is this limit configured in Junos?
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
✓
set interfaces ge-0/0/5 unit 0 family ethernet-switching port-security max-mac-count 2
MAC limit is configured under the interface-specific ethernet-switching-options hierarchy within the bridge-domains or vlans configuration, or directly under the interface if using port security.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
set forwarding-options storm-control interface ge-0/0/5 mac-limit 2
Why it's wrong here
Storm control manages broadcast, multicast, and unknown unicast traffic rates, not MAC address table limits.
- ✗
set protocols l2-learning global-max-mac-count 2 interface ge-0/0/5
Why it's wrong here
The l2-learning protocol hierarchy does not take a direct interface-level max MAC count command in this format.
- ✗
set bridge-domains vlan-data interface ge-0/0/5 mac-limit 2
Why it's wrong here
MAC limit syntax inside bridge-domains is structured differently and typically managed via ethernet-switching-options.
- ✓
set interfaces ge-0/0/5 unit 0 family ethernet-switching port-security max-mac-count 2
Why this is correct
Max MAC count is configured under port-security on the specific ethernet-switching interface.
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
About these practice questions
Courseiva writes every JNCIS-ENT question from scratch — 506 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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 JNCIS-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 JNCIS-ENT exam.