Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
   (hpvDest As Any, ByVal hpvSource As Long, ByVal cbCopy As Long)


'DECLARACIONES PARA SABER LA MAC
Private Const NCBASTAT As Long = &H33
Private Const NCBNAMSZ As Long = 16
Private Const HEAP_ZERO_MEMORY As Long = &H8
Private Const HEAP_GENERATE_EXCEPTIONS As Long = &H4
Private Const NCBRESET As Long = &H32
Private Type NET_CONTROL_BLOCK 'NCB
   ncb_command As Byte
   ncb_retcode As Byte
   ncb_lsn As Byte
   ncb_num As Byte
   ncb_buffer As Long
   ncb_length As Integer
   ncb_callname As String * NCBNAMSZ
   ncb_name As String * NCBNAMSZ
   ncb_rto As Byte
   ncb_sto As Byte
   ncb_post As Long
   ncb_lana_num As Byte
   ncb_cmd_cplt As Byte
   ncb_reserve(9) As Byte ' Reserved, must be 0
   ncb_event As Long
End Type
Private Type ADAPTER_STATUS
   adapter_address(5) As Byte
   rev_major As Byte
   reserved0 As Byte
   adapter_type As Byte
   rev_minor As Byte
   duration As Integer
   frmr_recv As Integer
   frmr_xmit As Integer
   iframe_recv_err As Integer
   xmit_aborts As Integer
   xmit_success As Long
   recv_success As Long
   iframe_xmit_err As Integer
   recv_buff_unavail As Integer
   t1_timeouts As Integer
   ti_timeouts As Integer
   Reserved1 As Long
   free_ncbs As Integer
   max_cfg_ncbs As Integer
   max_ncbs As Integer
   xmit_buf_unavail As Integer
   max_dgram_size As Integer
   pending_sess As Integer
   max_cfg_sess As Integer
   max_sess As Integer
   max_sess_pkt_size As Integer
   name_count As Integer
End Type
Private Type NAME_BUFFER
   name As String * NCBNAMSZ
   name_num As Integer
   name_flags As Integer
End Type
Private Type ASTAT
   adapt As ADAPTER_STATUS
   NameBuff(30) As NAME_BUFFER
End Type
Private Declare Function Netbios Lib "netapi32.dll" _
   (pncb As NET_CONTROL_BLOCK) As Byte
'Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
' (hpvDest As Any, ByVal _
' hpvSource As Long, ByVal _
' cbCopy As Long)
Private Declare Function GetProcessHeap Lib "kernel32" () As Long
Private Declare Function HeapAlloc Lib "kernel32" _
    (ByVal hHeap As Long, ByVal dwFlags As Long, _
     ByVal dwBytes As Long) As Long
Private Declare Function HeapFree Lib "kernel32" _
    (ByVal hHeap As Long, _
     ByVal dwFlags As Long, _
     lpMem As Any) As Long



Public Function GetMACAddress() As String
    'retrieve the MAC Address for the network controller
    'installed, returning a formatted string
    Dim tmp As String
    Dim pASTAT As Long
    Dim NCB As NET_CONTROL_BLOCK
    Dim AST As ASTAT
    'The IBM NetBIOS 3.0 specifications defines four basic
    'NetBIOS environments under the NCBRESET command. Win32
    'follows the OS/2 Dynamic Link Routine (DLR) environment.
    'This means that the first NCB issued by an application
    'must be a NCBRESET, with the exception of NCBENUM.
    'The Windows NT implementation differs from the IBM
    'NetBIOS 3.0 specifications in the NCB_CALLNAME field.
    NCB.ncb_command = NCBRESET
    Call Netbios(NCB)
    'To get the Media Access Control (MAC) address for an
    'ethernet adapter programmatically, use the Netbios()
    'NCBASTAT command and provide a "*" as the name in the
    'NCB.ncb_CallName field (in a 16-chr string).
    NCB.ncb_callname = "* "
    NCB.ncb_command = NCBASTAT
    'For machines with multiple network adapters you need to
    'enumerate the LANA numbers and perform the NCBASTAT
    'command on each. Even when you have a single network
    'adapter, it is a good idea to enumerate valid LANA numbers
    'first and perform the NCBASTAT on one of the valid LANA
    'numbers. It is considered bad programming to hardcode the
    'LANA number to 0 (see the comments section below).
    NCB.ncb_lana_num = 0
    NCB.ncb_length = Len(AST)
    pASTAT = HeapAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS _
             Or HEAP_ZERO_MEMORY, NCB.ncb_length)
    If pASTAT = 0 Then
        Debug.Print "memory allocation failed!"
        Exit Function
    End If
    NCB.ncb_buffer = pASTAT
    Call Netbios(NCB)
    CopyMemory AST, NCB.ncb_buffer, Len(AST)
    tmp = Format$(Hex(AST.adapt.adapter_address(0)), "00") & "-" & _
          Format$(Hex(AST.adapt.adapter_address(1)), "00") & "-" & _
          Format$(Hex(AST.adapt.adapter_address(2)), "00") & "-" & _
          Format$(Hex(AST.adapt.adapter_address(3)), "00") & "-" & _
          Format$(Hex(AST.adapt.adapter_address(4)), "00") & "-" & _
          Format$(Hex(AST.adapt.adapter_address(5)), "00")
    HeapFree GetProcessHeap(), 0, pASTAT
    GetMACAddress = tmp
End Function