View all questions & answers for the NSE 5 - FortiSwitch 7.6 Administrator Exam Materials exam


Question 34 Discussion

How does enabling an IGMP snooping proxy on FortiSwitch help reduce the number of IGMP reports processed by the IGMP querier? (Choose one answer)

  • A. By converting IGMP reports into broadcast packets to reach all VLAN members
  • B. By converting IGMP traffic to unicast
  • C. By suppressing duplicate IGMP reports within the VLAN
  • D. By forwarding IGMP reports only when the first member joins and the last member leaves
Correct Answer: D

Brave-Dump Clients Votes

C 50%
D 50%

Comments



javaughn Bryan 2025-12-11 02:24:34

Selected Answers: C


C is correct.

In large networks with a very high number of multicast receivers, the number of IGMP report messages can be considerable. Because FortiSwitch forwards IGMP reports to mRouter ports, an elevated number of multicast receivers can increase the system resource usage on the IGMP querier device.

To reduce the number of IGMP reports processed by the IGMP querier, you can enable an IGMP snooping proxy on FortiSwitch. When you enable an IGMP snooping proxy, FortiSwitch forwards IGMP reports only when the first member of a multicast group joins and when its last member leaves. When you enable IGMP snooping fast leave, FortiSwitch removes a member from the multicast layer 2 forwarding table immediately after receiving an IGMP report leave message. If you enable an IGMP snooping proxy, you can instruct FortiSwitch to wait for a period-10 seconds by default-before removing the member from the table.

PAGE: 257 | FORTISWITCH 7.6 ADMIN GUIDE

John 2025-12-20 21:05:23

Selected Answers: D


~D IS CORRECT~
C is misleading because of the phrase “within the VLAN.” Hosts still send IGMP reports inside the VLAN; IGMP snooping proxy reduces load on the IGMP querier by aggregating membership and forwarding reports upstream only on first join / last leave (to the mrouter/querier). That behavior matches D, not “suppressing duplicate reports within the VLAN.”

Fortinet states:

“When IGMP snooping proxy is enabled, FortiSwitch forwards IGMP membership reports to the IGMP querier only when the first member of a multicast group joins and when the last member leaves.”
— FortiSwitch 7.6 Administrator Study Guide, page 257

Fortinet does not say:

IGMP reports are suppressed within the VLAN

Hosts stop sending IGMP reports

Duplicate reports inside the VLAN are blocked

The behavior described is upstream aggregation toward the IGMP querier, not suppression of IGMP traffic within the VLAN.

Therefore, the wording in C (“within the VLAN”) is incorrect, and D correctly restates the study guide behavior.