VxRail: LCM Upgrade to 7.0.x/8.0.x Resets VDS Multicast Mode

Summary: Dell VxRail upgrades from 4.x to 7.0.x or 8.0.x results in Multicast filtering mode reset. Broadcom vSphere Virtual Distributed Switch (VDS) upgrades affect Microsoft Network Load Balancing (NLB). ...

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Symptoms

VxRail Lifecycle Management (LCM) completes VDS to 7.0.x or 8.0.x release without errors.
Microsoft Network Load Balancing (NLB) fails when Internet Group Management Protocol (IGMP)/Multicast Listener Discovery (MLD) snooping is enabled on the vSphere VDS.

Cause

By default, a VDS on 6.x has its Multicast filtering mode set to Basic (required for certain NLB applications):

VDS 6x Properties

However, when upgrading VDS to 7.x or 8.0.x version, Broadcom automatically sets Multicast filtering mode to default to IGMP/MLD snooping. This is the new default behavior for 7.0.x and 8.0.x and not expected to change in future releases.

Microsoft NLB has a configuration requirement to function correctly :(reference https://knowledge.broadcom.com/external/article?legacyId=75217This hyperlink is taking you to a website outside of Dell Technologies.)

  • The IGMP snooping tables must be build-up with an IGMP join message and In Microsoft NLB, the IGMP join message is not sent.
  • If IGMP snooping is enabled on the VDS, the virtual switch cannot build the lookup table for VIP of NLB and packets are dropped.

When the VDS upgrade is performed manually through the vCenter UI, an informational message indicates the change of this setting:

Warning during manual VDS upgrade

VxRail performs the automated VDS upgrade, potentially causing a Microsoft application NLB outage.
 

Resolution

VxRail LCM includes a precheck warning as of 7.0.405 release, referencing this knowledge base article:
 

Image illustrating the precheck warning.


If the issue has already occurred post VxRail LCM upgrade, then the VDS setting can be updated to allow NLB to function again:

  • From the Networking section on the impacted VDS - Configure - Properties - Choose Edit

Screenshot showing how to access the edit setting

  • Under Advanced - Multicast filtering mode - Select Basic mode and confirm with OK

Screenshot showing the multicast filtering mode 
VxRail LCM upgrade planning recommends preparing for such Microsoft NLB applications Virtual IP maintenance window during the final upgrade steps.

Affected Products

VxRail, VxRail Appliance Family, VxRail Appliance Series, VxRail Software
Article Properties
Article Number: 000196307
Article Type: Solution
Last Modified: 13 May 2026
Version:  10
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