mediumMultiple SelectObjective-mapped
CCNP Practice Question: Which two statements about IGMP snooping are…
Which two statements about IGMP snooping are true? (Choose two.)
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 unnecessary multicast flooding on a Layer 2 switch.
IGMP snooping operates on Layer 2 switches to constrain multicast traffic to only those ports that have interested receivers. It listens to IGMP messages between hosts and routers to build a forwarding table. It does not replace IGMP; it is complementary. The querier is elected based on the lowest IP address, not the highest. IGMP snooping does not modify IP multicast headers.
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 unnecessary multicast flooding on a Layer 2 switch.
Why this is correct
Correct because IGMP snooping allows the switch to forward multicast frames only to ports that have joined the group, reducing flooding.
- ✗
IGMP snooping uses the IGMP querier election process to select the switch with the highest IP address as the querier.
Why it's wrong here
Incorrect because the IGMP querier is elected based on the lowest IP address, not the highest.
- ✗
IGMP snooping can be configured to replace IGMP on the router interface.
Why it's wrong here
Incorrect because IGMP snooping is a Layer 2 feature that works alongside IGMP; it does not replace the IGMP protocol on routers.
- ✓
IGMP snooping listens to IGMP membership reports and leave messages to build a forwarding table.
Why this is correct
Correct because the switch examines IGMP messages to learn which ports have joined or left a multicast group.
- ✗
IGMP snooping modifies the IP header of multicast packets to include group membership information.
Why it's wrong here
Incorrect because IGMP snooping does not modify packets; it only inspects IGMP control messages to update its forwarding database.
About these practice questions
Courseiva writes every 350-401 question from scratch — 1,175 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 →
Same concept, more angles
1 more way this is tested on 350-401
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which three statements about IGMP snooping are true? (Choose three.)
medium- ✓ A.IGMP snooping reduces multicast flooding on a VLAN by forwarding traffic only to ports that have joined the group.
- ✓ B.IGMP snooping builds a Layer 2 forwarding table that maps multicast MAC addresses to switch ports.
- ✓ C.IGMP snooping forwards IGMP membership reports only toward the multicast router (querier).
- D.IGMP snooping suppresses all IGMP general queries from the multicast router.
- E.IGMP snooping requires PIM to be enabled on the switch.
Why A: 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.
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.