vuser2010
Contributor
Contributor

What mac-address is visible to physical switches?

Jump to solution

I have a Dell host with 4 pNics and vSphere 4.0 hypervisor. pNics are attached to a physical switch. Switch do not support CDP protocol (does support LLDP). On switch folding database, I do not see Dell pNICs mac addresses. Instead, I see mac-addresses with  VMWare OUIs (00:0c:29:xx:xx:xx).

What address is seen to the switches? Where can I find these VMWare hypervisor mac-addresses in VI Client or MOB? Is it vSwitch mac-address (i couldn't find vSwitch mac-address anywhere in VI client) ?

In MOB, I see following objects under HostNetworkInfo:

pnic     PhysicalNic[]
* pnic["key-vim.host.PhysicalNic-vmnic0"]
* pnic["key-vim.host.PhysicalNic-vmnic1"]
* pnic["key-vim.host.PhysicalNic-vmnic2"]
* pnic["key-vim.host.PhysicalNic-vmnic3"]
portgroup     HostPortGroup[]
* portgroup["key-vim.host.PortGroup-VM Network 16"]
* portgroup["key-vim.host.PortGroup-Management Network"]
* portgroup["key-vim.host.PortGroup-VMKernel"]
* portgroup["key-vim.host.PortGroup-MLAG Testbed"]

My understanding was that mac-address would be at vSwitch level and not at the port level.

Is there any other simple way to find (via LLDP?) where the host is connected (vSphere 4.0 or vSphere 4.1)?

Thank you, in advance.

1 Solution

Accepted Solutions
ATL2VEGAS
Enthusiast
Enthusiast

vuser2010,

Please award points if your question has been answered to close out your questions.

Thank You,

Andre

Andre Chambers Contract IT Consultant Medium & Enterprise Business Solutions AndreChambersLV@gmail.com 702-203-9068

View solution in original post

0 Kudos
6 Replies
weinstein5
Immortal
Immortal

The physical switch will see all MAC addresses both physical and virtual - but since none of the traffic is being generated from the physical NICs over time those physical MAC address will be removed from the physical switch MAC Address table because no traffic is associated with those NICs all traffic is being generated from the virtual machine and the corresponding virtual NIC and its virtual MAC Address.

There is no MAC address associated with the vSwitch -

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful
vuser2010
Contributor
Contributor

weinstein5,

Thanks for the reply.

On wire I see two types of VMWare mac-address. VMs' vNIC's mac-addresses (00:50:56: xx) and other VMWare addresses (00:0c:29: xx). What are these other mac-addresses? Are they portgroups mac-addresses? Are these there due to Hypervisor's management traffic and will they always be present?

I am trying to find a way to look into switch folding database to find which port host is connected to.

Thanks again.

0 Kudos
weinstein5
Immortal
Immortal

I believe one of the MAC address range is used by the virtual management NIC and the other is the virtual MAC Address of a VM -  as I said before port groups are not assigned a MAC address.

The MAC addresses can chang because whenever a VM is powered on a new MAC address is generated and is based the location where the VM is stored and the ESX hosts UUID - so if the VM is not powered off the virtual MAC address will not change

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful
0 Kudos
vuser2010
Contributor
Contributor

weinstein5,

Can you please carify "virtual management NIC"? Where can I see this mac-address in VI client or MOB?

You are right that port group (vSwitch) do not have mac-addresses. However, I see following in MOB:

Data Object Type: HostPortGroupPort
Parent Managed Object ID: host-9
Property Path: config.network.portgroup["key-vim.host.PortGroup-VMKernel"].port["key-vim.host.PortGroup.Port-33554435"]

Properties

Name Type Value
dynamicProperty DynamicProperty[] Unset
dynamicType string Unset
key string "key-vim.host.PortGroup.Port-33554435"
mac string[] "00:50:56:76:2c:dc"

That is, the following property of Host has mac address:

config.network.portgroup.port

What is this mac address?

thank you, once again. Its great help.

0 Kudos
ATL2VEGAS
Enthusiast
Enthusiast

Using the vsphere client navigate to the network configuration for your host. Under the network configuration go to the properties of the vswitch that contains the managment network. You should see the management network mac address displayed on the right hand side.  Since host management relies on a vmkernel port the mac address shown should be the same as the mac address shown in the output included in your previous post.

Data Object Type: HostPortGroupPort
Parent Managed Object ID: host-9
Property Path: config.network.portgroup["key-vim.host.PortGroup-VMKernel"].port["key-vim.host.PortGroup.Port-33554435"]

Properties

Name Type Value
dynamicProperty DynamicProperty[] Unset
dynamicType string Unset
key string "key-vim.host.PortGroup.Port-33554435"
mac string[] "00:50:56:76:2c:dc"

-Andre

Andre Chambers Contract IT Consultant Medium & Enterprise Business Solutions AndreChambersLV@gmail.com 702-203-9068
0 Kudos
ATL2VEGAS
Enthusiast
Enthusiast

vuser2010,

Please award points if your question has been answered to close out your questions.

Thank You,

Andre

Andre Chambers Contract IT Consultant Medium & Enterprise Business Solutions AndreChambersLV@gmail.com 702-203-9068
0 Kudos