ESXi

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  • 1.  2 VMHosts; Same MAC Addr on both vSwitch2

    Posted Jul 14, 2010 07:27 PM

    I have discovered that I have the same mac address 00:50:56:78:c7:e2 on vSwitch2 on 2 separate physical ESXi servers. How do I change one of them? vSwitch2 is using NIC teaming and therefore not choosing the NIC's address.

    Thank you in advance!

    Brian



  • 2.  RE: 2 VMHosts; Same MAC Addr on both vSwitch2

    Posted Jul 14, 2010 07:40 PM

    Welcome to the Forums I am a little confused - you say you have two different ESXi servers presenting a single MAC Address is this MAC address assigned to a VM or vmkernel port? You mention only a single vSwitch and that If the vSwitch is configured for NIC teaming using the IP Hash methodology then the same MAC address will show up on multiple ort on your physical Network switch - in this configuration you will need to make sure your physical witch is configured fro LACP

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  • 3.  RE: 2 VMHosts; Same MAC Addr on both vSwitch2

    Posted Jul 14, 2010 08:07 PM

    The same MAC address is assigned to the vmKernel of vSwitch 2 on both machines. Luckily it was just a standby backup for my 10G network. I noticed "redundant path" error messages in the event log.

    What I did to get around the problem was to remove the associated ethernet cables, added a 2nd vmkernel with an ip address in a different subnet to the 2nd esxi server. Verified the MAC address was not used in any of my other vmKernels. I then removed the original vmkernel, then changed the IP address on the new kernel giving me the same ip address but with a different mac address. Reconnected the cables and tested with pings and verified paths to the datastores.

    It now works fine.

    Do I have to worry about a reboot re-assigning MAC addresses?

    Again we are not talking about the Virtual Machines. This is strictly about the hosts. Sorry about the vagueness in my original post.

    Thanks,

    Brian



  • 4.  RE: 2 VMHosts; Same MAC Addr on both vSwitch2

    Posted Jul 14, 2010 11:56 PM

    Hi,

    because the vmware assigning mac address algorithm this kind of issue is very uncommon.

    Anyway the vmkernel mac address can be statically assigned to a vmkernel vmnic using this command on the unsupported esxi host text console:

    vimsh hostsvc/net/vnic_set --vnic-mac=00:50:56:xx:xx:xx vmk1

    Check some more information about this command here.

    Hope this helps :smileyhappy:



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    Pablo

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  • 5.  RE: 2 VMHosts; Same MAC Addr on both vSwitch2

    Posted Jul 15, 2010 12:18 AM

    Thanks for the info! My main concern is that the MAC I have now might change with a reboot since I now have different MAC addresses and everything is working fine. Do you think I'm safe now or do I need to "statically" assign the address?

    I have been told by others that I should be fine now.

    Regards,

    Brian



  • 6.  RE: 2 VMHosts; Same MAC Addr on both vSwitch2

    Posted Jul 15, 2010 12:46 AM

    Hi,

    it should be fine now.

    Anyway it can happens again, but it is very uncommon..

    You have to think about the fact vmware prevents to have duplicated mac in the same host. But as you already know, it can happens with different hosts (but i repeat again, it is very very very rare).

    I really don't know any vmware administrators that set statically the MAC addresses to prevent this kind of issue.

    Please remember to mark any correct or helpful answer. This is the way to award users that help others :smileyhappy:



    Regards/Saludos,
    Pablo

    Please consider awarding

    any helpful or corrrect answer. Thanks!! -

    Por favor considera premiar

    cualquier respuesta útil o correcta. ¡¡Muchas gracias!!

    Virtually noob blog