JNCIP-ENT IP Multicast Practice Question
An enterprise network administrator is configuring PIM Sparse-Mode and needs to control which multicast groups are allowed to be joined or forwarded through the network. Which THREE methods or configuration elements can be used in Junos OS to filter multicast join messages or control group memberships? (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 an IGMP access policy under [edit protocols igmp interface <name> policy] to restrict local host group memberships.
In Junos, multicast group filtering can be achieved by applying policy frameworks to PIM joins, configuring IGMP access-lists or policies to restrict host joins, and setting SSM mapping filters.
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 a firewall filter family inet filter-name on the loopback interface matching destination port 639.
Why it's wrong here
Port 639 is used for MSDP, not for filtering PIM join messages or host IGMP memberships.
- ✗
Apply a bridge-domain filter under [edit bridge-domains] blocking destination MAC address 01:00:5E:00:00:01.
Why it's wrong here
01:00:5E:00:00:01 is the MAC address for all-hosts (224.0.0.1), blocking it would disrupt basic IP host communication entirely rather than filtering specific multicast groups.
- ✓
Configure an IGMP access policy under [edit protocols igmp interface <name> policy] to restrict local host group memberships.
Why this is correct
IGMP policies can be applied on interfaces to control which groups directly connected hosts are permitted to join.
- ✓
Apply a policy statement under [edit protocols pim join-policy] to filter incoming (*,G) and (S,G) joins.
Why this is correct
The join-policy feature under protocols pim allows operators to use routing policies to accept or reject PIM join messages based on source and group addresses.
- ✓
Configure SSM mapping using [edit protocols igmp ssm-mapping] to translate standard IGMPv2 joins into SSM range joins.
Why this is correct
SSM mapping allows mapping arbitrary groups or filtering how IGMPv2 reports map into the SSM range.
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.