Duplicate MAC address on Client PC

  • Hi, all expert.

    I m now host openvpn server on pfsense using PKI Tunnel. My local network A and local network B are using duplicate OS machine. It is using something like "Ghost" and Diskless Operating system. OS is window XP Home SP2. The Clients was successfully connected to Server but cannot communicate with each others. Checked the duplicate-cn and client-to-client. Each OS Client got successful assigned OpenVPN IP. I form some test and finally get the result: the client's PC got duplicate MAC Address issue for the openvpn tap virtual network adaptor.

    My problem:
    All the client PCs got cloned OS image and hey have the same MAC address and this will cause the issue that "crash" MAC Address when connected to openvpn server. Problem is I cannot manually change all the MAC address because once the machine restart, the OS will back to initially condition. Can any expert know how to write the script to change the MAC address of TAP network adaptor automatically according ip address i need to assign? I try to export the registry and change the mac and patch it to system but not successful. I only found the way that i can manually change at device manager/ advance properties. I need to click OK then only successful change the mac address. If i patch the registry, it only change in figure but when i do ipconfig /all in command promnt it will show that the mac address is not yet change..

    The openvpn can successfully link up IF mac address of tap network adaptor is not same each other.

    Any solution for this??

    Thank you.

  • I'm not sure of an answer, but I think you might have better luck with the OpenVPN mailing list. Someone there has likely dealt with this before.

  • Hi,
    I got found a solution by this idea:

    Patch the registry to change the MAC address according IP. Disable the tap adaptor and enable back. The mac address of tap adaptor will changed to new one. Then enable openvpn client GUI. It should work.

    Now will start work out the solution… or some Programming expert can help on this?


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