My network card broke and I got a new one. Instead of registering it with the IT guys upstairs, I cloned the MAC of one of our unused machines.

I'm not being given an address at all, despite the unused machine still working on the network when being replugged in.

The problem I realise is not the MAC, but how else does the network know to reject my machine?

My old network card worked fine on my linux box within their windows network. Not once did I have to install a certificate.

What is going on?

  • 4
    Why don't you go and ask "the IT guys upstairs". It'll be way simpler and quicker than trying to guess what you did wrong or explain 802.1x to you.
    – Stephane
    Commented Oct 6, 2016 at 11:34
  • 2
    Trying to work around your IT team is actively discouraged here for several reasons: 1/ it can get you into trouble 2/ many posters here spend their day having to deal with the problem created by shadow ITs and users who attempt to work around your security policies for some reason.
    – Stephane
    Commented Oct 6, 2016 at 11:36
  • @Stephane thanks, it's just owning up to a new NIC means I'll have to explain what happened to the old one.... I thought the problem might be 802.1x, but I thought that required certificates to be installed on all machines. I understand you don't have the energy to explain the ins/outs of 802.1x, but any quick links would be much appreciated
    – tetris11
    Commented Oct 6, 2016 at 13:21

1 Answer 1


You should go talk to your IT guys. It will probably be annoying and painful, but the alternative is likely worse (maybe not immediately, but eventually). From the sounds of it, the network probably has some form of MAC/port filtering, and the MAC address you're using is only able to receive an address at the specific physical port.

As someone who once was one of "the IT guys upstairs," if you did this on my network and I had to find out about it the hard way, I would have made an example of you. NIC cards are not expensive, and break all the time. If you just go and admit that you broke yours, they may give you a hard time, but that would probably be the end of it.

  • Wow, okay fair I guess I should just suck it up. So just for my understanding - the MAC is registered to a specific wall socket?
    – tetris11
    Commented Oct 6, 2016 at 21:21

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