Option Explicit

Private Const NCBASTAT = &H33
Private Const NCBNAMSZ = 16
Private Const HEAP_ZERO_MEMORY = &H8
Private Const HEAP_GENERATE_EXCEPTIONS = &H4
Private Const NCBRESET = &H32
Private Type 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 NCB) 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

Private Function EthernetAddress(LanaNumber As Long) As String
  Dim udtNCB      As NCB
  Dim bytResponse  As Byte
  Dim udtASTAT    As ASTAT
  Dim udtTempASTAT As ASTAT
  Dim lngASTAT    As Long
  Dim strOut      As String
  Dim x            As Integer
  udtNCB.ncb_command = NCBRESET
  bytResponse = Netbios(udtNCB)
  udtNCB.ncb_command = NCBASTAT
  udtNCB.ncb_lana_num = LanaNumber
  udtNCB.ncb_callname = "* "
  udtNCB.ncb_length = Len(udtASTAT)
  lngASTAT = HeapAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS Or HEAP_ZERO_MEMORY, udtNCB.ncb_length)
  strOut = ""
  If lngASTAT Then
    udtNCB.ncb_buffer = lngASTAT
    bytResponse = Netbios(udtNCB)
    CopyMemory udtASTAT, udtNCB.ncb_buffer, Len(udtASTAT)
    With udtASTAT.adapt
      For x = 0 To 5
        strOut = strOut & Right$("00" & Hex$(.adapter_address(x)), 2)
      Next x
    End With
    HeapFree GetProcessHeap(), 0, lngASTAT
  End If
  EthernetAddress = strOut
End Function

Private Sub Command1_Click()
    Me.Caption = EthernetAddress(0)
    MsgBox "NetCard Number:" + (Chr(13)) + EthernetAddress(0)
End Sub