Getting the Network Card MAC Address

Option Explicit Public

Const NCBASTAT As Long = H33
Public Const NCBNAMSZ As Long = 16
Public Const HEAP_ZERO_MEMORY As Long = H8
Public Const HEAP_GENERATE_EXCEPTIONS As Long = H4
Public Const NCBRESET As Long = H32

Public 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

Public 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
  
Public Type NAME_BUFFER
   name As String * NCBNAMSZ
  
name_num As Integer
   name_flags As Integer
End Type

Public Type ASTAT
   adapt As ADAPTER_STATUS
   NameBuff(30) As NAME_BUFFER
End Type

Public Declare Function Netbios Lib "netapi32.dll" _
   (pncb As NET_CONTROL_BLOCK) As Byte
    
Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
   (hpvDest As Any, ByVal _
    hpvSource As Long, ByVal _
    cbCopy As Long)
    
Public Declare Function GetProcessHeap Lib "kernel32" () As Long Public Declare Function HeapAlloc Lib "kernel32" _
    (ByVal hHeap As Long, ByVal dwFlags As Long, _
     ByVal dwBytes As Long) As Long
    
Public 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