Question

I’ve heard it’s not possible with my current library of winpcap.

Is this really true? I see lots of examples on the net but then comments saying “This doesn’t work”.

What’s the best way to get a MAC address of the local machine?

Answer 1

One common method is using bits from a UUID, but this isn’t entirely dependable. For example, it’ll return a value even on a machine that doesn’t have a network adapter.

Fortunately, there is a way that works dependably on any reasonably recent version of Windows. MSDN says it only goes back to Windows 2000, but if memory serves, it also works on NT 4, starting around SP 5, in case anybody’s still using NT 4.

#include <windows.h>
#include <iphlpapi.h>
#include <stdio.h>

int main() {         
    IP_ADAPTER_INFO *info = NULL, *pos;
    DWORD size = 0;

    GetAdaptersInfo(info, &size);

    info = (IP_ADAPTER_INFO *)malloc(size);

    GetAdaptersInfo(info, &size);

    for (pos=info; pos!=NULL; pos=pos->Next) {
        printf("\n%s\n\t", pos->Description);
        printf("%2.2x", pos->Address[0]);
        for (int i=1; i<pos->AddressLength; i++)
            printf(":%2.2x", pos->Address[i]);
    }

    free(info);
    return 0;
}

Please forgive the ancient C code…