3rd party multicast application fails to communicate each other after migrated to NSX Segment from distributed port group with promiscuous mode accepted.

Products

• VMware NSX

Issue/Introduction

• Migrate the VM from distributed port group with promiscuous mode accepted.
• Multicast packets such as VRRP cannot be seen on Guest OS.
  • Packet capture at Guest OS does not show the multicast packets.
• The multicast packets were sent from 3rd party application including:
  • Fujitsu IPCOM
• Port status does not contain a multicast mac address for the multicast application in multicastAddresses in accepted or requested filters except 01:00:5e:00:00:01 which is for All Host, 224.0.0.1.
  Guest OS cannot receive multicast packets unless Guest OS requests the mac address and the associated port accepts the mac address.
  # vsish -e get /net/portsets/<DvsPortset>/ports/{port_id}/status
  port {
   port index:<port index>
   vnic index:<vnic index>
   portCfg:########-####-####-####-############
   dvPortId:########-####-####-####-############
   clientName:<VM Name>.eth#
   clientType: 5 -> VMM Virtual NIC
   clientSubType: 9 -> Vmxnet3 Client
   world leader:<world leader id>
   flags: 0x40093 -> IN_USE ENABLED WORLD_ASSOC DVS_PORT CONNECTED
   Impl customized blocked flags:0x00000000
   Passthru status: 0x8 -> DISABLED_BY_HOST
   fixed Hw Id:<mac address>:
   ethFRP:frame routing {
      requested:filter {
         flags:0x0000001b
         unicastAddr:<unicast mac address>:
         numMulticastAddresses:1
         multicastAddresses:01:00:5e:00:00:01,
         LADRF:[0]: 0x0
         [1]: 0x0
      }
      accepted:filter {
         flags:0x0000000b
         unicastAddr:<unicast mac address>:
         numMulticastAddresses:1
         multicastAddresses:01:00:5e:00:00:01,
         LADRF:[0]: 0x0
         [1]: 0x0
      }
   }
   filter supported features: 0 -> NONE
   filter properties: 0 -> NONE
   rx mode: 0 -> INLINE
   tune mode: 0 -> default
   fastpath switch ID:0xffffffff
   fastpath port ID:0xffffffff
}

Environment

NSX 4.x
NSX-T Data Center 3.x

Cause

Some 3rd party application does not use system call to join multicast group.

Depending on Guest OS Kernel, the system call to join multicast group is different.

• In Linux, IP_ADD_MEMBERSHIP passed to setsockopt().

NSX Segment captures the system call and accepts multicast address.

Distributed port group with promiscuous mode accepted does not filter multicast packets based on requested / accepted filters.

Resolution

Workarounds:

• In Linux, the following command joins an interface to a multicast group.
  ipmaddr add <multicast mac address> dev <device name>