Dim mc As ManagementClass
Dim moc As ManagementObjectCollection
Dim mo As ManagementObject
mc = New ManagementClass("Win32_NetworkAdapterConfiguration")
moc = mc.GetInstances() ' Get all network adapter instances
For Each mo In moc
If mo.Item("IPEnabled") = True Then
TextBox1.Text = mo.Item("MacAddress").ToString()
End If
mo.Dispose()
Next