mediumMultiple SelectObjective-mapped
CCNP Practice Question: Which three statements about IGMP snooping are…
Which three statements about IGMP snooping are true? (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
✓
IGMP snooping reduces multicast flooding on a VLAN by forwarding traffic only to ports that have joined the group.
IGMP snooping optimizes multicast forwarding at Layer 2 by monitoring IGMP messages. It builds a snooping table, forwards reports only to the querier, and can be configured with static entries. It does not suppress queries or require PIM.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
IGMP snooping reduces multicast flooding on a VLAN by forwarding traffic only to ports that have joined the group.
Why this is correct
Correct because IGMP snooping examines IGMP join messages and builds a forwarding table so multicast frames are sent only to interested receivers.
- ✓
IGMP snooping builds a Layer 2 forwarding table that maps multicast MAC addresses to switch ports.
Why this is correct
Correct because the snooping switch records which ports have active members for each multicast group, using the multicast MAC address derived from the IP group address.
- ✓
IGMP snooping forwards IGMP membership reports only toward the multicast router (querier).
Why this is correct
Correct because the switch forwards IGMP reports only out of the port where the querier (multicast router) is connected, preventing unnecessary flooding to other hosts.
- ✗
IGMP snooping suppresses all IGMP general queries from the multicast router.
Why it's wrong here
Incorrect because IGMP snooping does not suppress queries; it forwards them to all ports in the VLAN so hosts can respond. Queries are only suppressed in IGMP proxy reporting, which is a different feature.
- ✗
IGMP snooping requires PIM to be enabled on the switch.
Why it's wrong here
Incorrect because IGMP snooping operates at Layer 2 and does not require PIM; it is independent of Layer 3 multicast routing protocols.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco 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 350-401 exam.