Nasty Problem - Fixed, Don't get caught out

  • I had a real pig of a problem today, and wanted to let you all know about it, so you don’t spend as many hours as I do finding it.

    The symptoms of a duplicate IP are, one box works, reboot the duplicate IP and the other box works, then the first stops.

    I imaged one server then sent the image down to 5 other machines. none of the other machines were accessible across the network, checked all the obvious IPs etc, no joy.

    It turned out to be the MAC address. The image had taken the mac address up, and all the imaged servers had the mac address from the source image.

    Easy enough to fix by defining a new mac in the adapter’s properties, but a pig to spot.

    I hope this helps someone else out there.


  • @Junkhacker
    Well this was the interesting bit, it was all physical, the MACs imaged up were those of the physical adapters, but Hyper-v was “moving” the physical MACs to it’s internal network cards, and then of course imaging the software MACs up. Interesting, a pain but quite interesting.

  • I’ve been looking into this, and have spoken to one of our MCT instructors.
    The machines I was imaging were Server 2012 R2, with Hyper-v. The Macs were duplicated on all the images. The instructor pointed out that Hyper-v moves the original Mac into software and uses the physical card as a glorified pass through device, so in effect the physical Mac becomes software, which explains how the situation arose.

    I hope this helps anyone else imaging 2012 R2 Servers.

    Could you mark this as solved and edit the title to “Nasty Problem - Fixed, Don’t get caught out when imaging Hyper-V Hosts”

  • @Julianh Sounds good, ask for help if you need - don’t forget us!

  • Hi Wayne,

    I have a VMware troubleshooting course to finish off updating, but afterwards I should have some time and more importantly kit free in early May. I could have a go then if that’s ok.


  • @Julianh Would you be willing to build a test server with FOG Trunk on it and see if the problem exists in our developmental version of FOG? It’d be greatly appreciated and you’d be doing the fogproject a solid.

  • The machines were built for me, but they use the realtek Lan card on the ASUS A88XM-Plus mother boards, Fog v 1.20 on unbuntu 14.04, 6 core AMDs with 32 GB ram and SSDs.

    I was imaging up Server 2012, which normally works fine, one image per Physical server normally. But it’s eating my storage, so I thought I’d try 1 image to multiple servers, looks like I’m buying some more disks.

  • @Julianh said in [Nasty Problem - Fixed:


    It is all physical, which is why it’s supposed to be impossible.

    Well now you have all of our interest. Please do spill the beans about all involved hardware AND the fog version you’re using.

  • Developer

    @Julianh said in [Nasty Problem - Fixed:

    Easy enough to fix by defining a new mac in the adapter’s properties, but a pig to spot.

    what kind of network adapter was it then? can you give us the make/model?

  • Hi,

    It is all physical, which is why it’s supposed to be impossible.

  • Developer

    was it a virtual network device? like the virtualbox host-only network adapter?

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