Changing multicast filtering mode on distributed switch from IGMP/MLD snooping, to Basic.

Products

• VMware vSphere ESXi 7.0
• VMware vSphere ESX 8.x

Issue/Introduction

When upgrading a distributed virtual switch (vDS) from 6.7 to 7.0, 'Multicast snooping' mode is enabled by default on the distributed switch (vDS). 

Cause

IGMP multicast snooping mode, is an efficiency feature that is added onto the vDS, which allows multicast traffic direction to be more accurate. 

This mode may be undesired in certain situations, where a reversion back to 'Basic' multicast filtering is needed. 

Resolution

There is no impact, outside the virtual switch, when changing from 'IGMP/MLD snooping' mode to 'Basic' mode on the vDS. 

Additional Information

1. Multicast Filtering Modes
2. Understanding IP Multicast in ESXi
3. IGMP/MLD snooping when enabled makes Virtual IP in Microsoft NLB (Network Load Balancer) not reachable
4. Multicast Filtering Mode in vSphere 8.0: A Comprehensive Guide
5. Japanese KB:https://knowledge.broadcom.com/external/article/409434