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Unexpected MAC address behavior for Mobile Broadband Interfaces in Windows - Microsoft Support

Thread starter TWF Bot
Start date May 16, 2025

Thread Author

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hacxx

VIP

May 19, 2025

Windows generates MAC addresses for Mobile Broadband interfaces based on the modem’s IMEI, which can cause unexpected OUIs unrelated to the hardware manufacturer. This behavior affects device identification relying on consistent or vendor-specific MAC addresses. The generated MAC is only used within Windows networking and is visible via tools like ipconfig. USB cellular modems get their MAC from Microsoft’s driver, with no override option. PCIe modems allow developers to set MAC addresses using specific NetAdapterCx APIs. Understanding this helps avoid misidentification and better manage network policies.