how to display the MAC address of client?

I have a client server program using UPD created in MFC. In the server there are two listboxes. The first one displays the ip addresses of the connected clients.
I want the second listbox to display the MAC address when i click the ip address from the listbox.

So how can I display the MAC address of the client by clicking the ip address in the first listbox?

so i used this code to get the MAC address:

Code:

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IP_ADAPTER_INFO AdapterInfo[16];                        // Allocate information for up to 16 NICs
        DWORD dwBufLen = sizeof(AdapterInfo);                // Save the memory size of buffer

        DWORD dwStatus = GetAdaptersInfo(                        // Call GetAdapterInfo
                AdapterInfo,                                                        // [out] buffer to receive data
                &dwBufLen);                                                                // [in] size of receive data buffer
        assert(dwStatus == ERROR_SUCCESS);                        // Verify return value is valid, no buffer overflow

        PIP_ADAPTER_INFO pAdapterInfo = AdapterInfo;// Contains pointer to current adapter info
        do {
                PrintMACaddress(pAdapterInfo->Address);        // Print MAC address
                pAdapterInfo = pAdapterInfo->Next;                // Progress through linked list
        }
        while(pAdapterInfo);                                                // Terminate if last adapter
}

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the code above just provides the currents computer mac address so it doesn't matter which ip address i click in the listbox because it only displays the same mac address

It may be that you have too small of an array. Try calling the GetAdaptersInfo() with a NULL and a zero to get the needed size.

You may be getting no results so your "MAC" may be garbage. Instead of a do/while, use just a while loop.

Here is a clip of code I use all the time:

Code:

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        for(pAdapterInfo= AdapterInfo; pAdapterInfo; pAdapterInfo= pAdapterInfo->Next )
        {
                DWORD dwIP = ntohl(inet_addr(pAdapterInfo->IpAddressList.IpAddress.String));
                DWORD dwMask = ntohl(inet_addr(pAdapterInfo->IpAddressList.IpMask.String));
                BYTE MAC[6];
                CopyMemory(MAC, pAdapterInfo->Address, 6);

                // Do something

        }

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-Erik

P.S. Also take a look at GetIpNetTable() and SendARP().