JNCIS-ENT Layer 2 Security Practice Question
You need to write a Layer 2 firewall filter to drop inbound frames with a specific source MAC address on an EX Series switch. Where must this filter be applied to take effect?
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
✓
Applied to the input of an interface or VLAN under family ethernet-switching.
Layer 2 firewall filters matching MAC addresses or Ethernet headers must be applied to the input of an interface or VLAN using the family ethernet-switching context.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Applied to the routing-instance forwarding table.
Why it's wrong here
Layer 2 filters are applied at the interface or VLAN level for ethernet-switching.
- ✗
Applied globally under system services l2-firewall.
Why it's wrong here
Junos does not have a global system services l2-firewall hierarchy.
- ✓
Applied to the input of an interface or VLAN under family ethernet-switching.
Why this is correct
Layer 2 filters operate on family ethernet-switching and are typically applied to ingress interfaces or VLANs.
- ✗
Applied to the output of the VLAN interface under family inet.
Why it's wrong here
Layer 2 filters use family ethernet-switching and are applied to input, not inet output.
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.