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Layer 2 SecurityhardMultiple SelectObjective-mapped

JNCIS-ENT Layer 2 Security Practice Question

An administrator configures a Layer 2 firewall filter to drop broadcast packets while permitting unicast traffic on an access VLAN. Which THREE configuration elements are required to implement this filter properly? (Choose three)

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 filter action as 'discard' for the broadcast term.

Implementing this filter requires defining the family ethernet-switching context, writing a term matching broadcast destination MAC addresses with action discard, and applying the filter to the VLAN or interface.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Enable active router-advertisement snooping to support the filter.

    Why it's wrong here

    RA snooping is unrelated to basic Layer 2 MAC filtering.

  • Apply the filter under the 'family inet' routing protocol hierarchy.

    Why it's wrong here

    Family inet is for Layer 3 IP traffic, not Layer 2 MAC filters.

  • Configure the filter action as 'discard' for the broadcast term.

    Why this is correct

    The discard action drops the matching broadcast traffic.

  • Define the filter under 'family ethernet-switching'.

    Why this is correct

    Layer 2 filters require family ethernet-switching.

  • Use a match condition for destination MAC address broadcast 'ff:ff:ff:ff:ff:ff'.

    Why this is correct

    Matching broadcast frames requires specifying the broadcast destination MAC address.

Visual reference

Switch VLAN 10 Sales (192.168.10.0/24) PC-A PC-B VLAN 20 HR (192.168.20.0/24) PC-C PC-D Router VLANs isolate traffic — inter-VLAN routing requires a Layer 3 device

Quick reference

Access Control Model Comparison

ModelAcronymWho Controls Access?Best For
Discretionary Access ControlDACResource ownerSmall teams, file shares
Mandatory Access ControlMACSystem / security labelsClassified govt / military
Role-Based Access ControlRBACAdministrator (via roles)Enterprise environments
Attribute-Based Access ControlABACPolicy engine (user + resource attributes)Fine-grained, dynamic policies
Rule-Based Access ControlRuBACSystem rules / ACLsFirewall rules, network ACLs

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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 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.