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Multicast MAC Addresses in VMware vSwitches

Harrris
Harrris asked
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Hello,

We have 5 ESX Servers and vCenter server, both version 5.5. We use standard vSwitches on each ESX server and a bond (with 2 physical ethernet ports) on each server that we use to pass traffic for various VLANs.

I noticed that network packets sent to a multicast destination MAC addresss, are flooded to all the VMs connected to the same vSwitch on the same host.

Is there a way to configure the VMs or the vSwitch, so that packets sent to a particular multicast MAC address will be delivered only to some of the VMs? i.e. to assign a second MAC address on a VM via CLI, apart from the primary MAC assigned to the VM? or maybe we can achieve this by using a distributed virtual switch instead of the standard vSwitch?

We need multicast traffic for various clusters of systems (servers, firewalls, etc), so we can't really avoid it.

Thanks,
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Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Commented:
I noticed that network packets sent to a multicast destination MAC addresss, are flooded to all the VMs connected to the same vSwitch on the same host.

This is correct, and they will also be sent out to other ports, on physical switches and devices.

Is this causing you an issue ?

This is why some organisation disable multicast, because the are paranoid, that it impacts services!
Harrris

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Commented:
Not causing a particular problem but since some of this traffic carries sensitive data, I'm wondering if there is a way to avoid this. Can we configure the hypervisor to deliver packets for a particular MAC address only to a specific VM?
VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017
Commented:
Can we configure the hypervisor to deliver packets for a particular MAC address only to a specific VM?

There are no options within ESXi networking, to prevent traffic leaving a VM, and multicasting to other network ports.