How to find what vNIC is using what pNIC on ESX 4

[bfrank81]

So I remember in ESX 3 you could use "esxtop network" and find what a VMs vNIC was mapped to as it's uplink but in ESX 4 it looks different.  I've been searching for the answer and cannot find it anywhere.

So here is the situation:

I have a Dell M610 blade that has 2 x pNICs, 1 x vSwitch and mulitple port groups.

How do I find what pNIC the traffic for my individual VMs are using?

Thanks!

[mittim12]

I'm not sure I understand the problem.  If you know what vmnic the VM is using then that vmnic can only corospond to singole physical nic.    Once you know the vmnic you can look at the host on vCenter to figure out which physical NIC that is.  

[bfrank81]

If I have VM connected to a vSwitch with 2 Physical Adapters than ESX will pin the vmnic to one of the physical NICs for it's traffic.  As far as I understand it this will stay this way until an event such as the NIC being disconnected or something similar.  The question is how do I find which physical adapter ESX has chosen for a particular VM?

[mittim12]

Your vmnic0, 1, 2, 3 are assigned to the vSwitch and are associated with physical adapters on the server.  These associations do not change.   What may change is the vmnic that the guest is pinned to.    So if vmnic0 is associated with physical NIC1 then it should always have that association unless you reinstall the hypervisor or manually change it.

Does that make sense?

[fgl · Accepted solution]

Are you talking about 'esxtop' and then hitting 'n' within esxtop?

This will show you which vnic each vm is using and then from the host configuration you can see which pnic is mapped to the vnic.

[AndreTheGiant]

Another way (more complicated, but generic) could be watch the arp table of the physical switch and check on which port is the MAC address of your VM.

Andre

[bfrank81]

Ahh that is what I was doing wrong.  I  was running the command esxtop network and thinking that was the correct way to view it.  It's not.  You have to type esxtop hit enter then hit n and it shows you in the column there what VM is using what vmnic and from there I can figure out what physical nic.  Thanks!