Question

How to get MAC address of client machine in c# and vb.net

Answer 1

I am not sure what you mean by client machine, because you can only get the MAC address of a NIC of the machine your application executes under.

For this you could use ManagementClass:

C#:

using (var mc = new ManagementClass("Win32_NetworkAdapterConfiguration"))
{
    foreach(ManagementObject mo in mc.GetInstances())
    {
        Console.WriteLine(mo["MacAddress"].ToString());
    }
}

VB.NET:

Using mc As New ManagementClass("Win32_NetworkAdapterConfiguration")
    For Each mo As ManagementObject In mc.GetInstances()
        Console.WriteLine(mo("MacAddress").ToString())
    Next
End Using