HOWTO: Get Network Adapter Address from Visual Basic

• Microsoft Visual Basic Professional and Enterprise Editions for Windows, versions 4.0, 5.0

SUMMARY

IPX and NETBIOS interfaces require network addresses. This article presents a step-by-step example on how to use Netbios API call to get the network adapter addresses from Microsoft Visual Basic.

MORE INFORMATION

Step-by-Step Example

1. Create a new Standard EXE from Visual Basic. Form1 is created by default.

2. Add a CommandButton to Form1. Its default name is Command1.

3. Add the following code to the General Declarations section of Form1:

   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 'Integer
           ncb_retcode As Byte 'Integer
           ncb_lsn As Byte 'Integer
           ncb_num As Byte ' Integer
           ncb_buffer As Long 'String
           ncb_length As Integer
           ncb_callname As String * NCBNAMSZ
           ncb_name As String * NCBNAMSZ
           ncb_rto As Byte 'Integer
           ncb_sto As Byte ' Integer
           ncb_post As Long
           ncb_lana_num As Byte 'Integer
           ncb_cmd_cplt As Byte  'Integer
           ncb_reserve(9) As Byte ' Reserved, must be 0
           ncb_event As Long
      End Type
      Private Type ADAPTER_STATUS
           adapter_address(5) As Byte 'As String * 6
           rev_major As Byte 'Integer
           reserved0 As Byte 'Integer
           adapter_type As Byte 'Integer
           rev_minor As Byte 'Integer
           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
   
   

4. Add the following code to Command1_Click event procedure:

      Sub Command1_Click()
          Dim myNcb As NCB
          Dim bRet As Byte
          myNcb.ncb_command = NCBRESET
          bRet = Netbios(myNcb)
   
          myNcb.ncb_command = NCBASTAT
          myNcb.ncb_lana_num = 0
          myNcb.ncb_callname = "*               "
   
          Dim myASTAT As ASTAT, tempASTAT As ASTAT
          Dim pASTAT As Long
          myNcb.ncb_length = Len(myASTAT)
          Debug.Print Err.LastDllError
          pASTAT = HeapAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS _
                   Or HEAP_ZERO_MEMORY, myNcb.ncb_length)
          If pASTAT = 0 Then
             Debug.Print "memory allcoation failed!"
             Exit Sub
          End If
          myNcb.ncb_buffer = pASTAT
          bRet = Netbios(myNcb)
          Debug.Print Err.LastDllError
          CopyMemory myASTAT, myNcb.ncb_buffer, Len(myASTAT)
          MsgBox Hex(myASTAT.adapt.adapter_address(0)) & " " & _
                 Hex(myASTAT.adapt.adapter_address(1)) _
                 & " " & Hex(myASTAT.adapt.adapter_address(2)) & " " _
                 & Hex(myASTAT.adapt.adapter_address(3)) _
                 & " " & Hex(myASTAT.adapt.adapter_address(4)) & " " _
                 & Hex(myASTAT.adapt.adapter_address(5))
          HeapFree GetProcessHeap(), 0, pASTAT
      End Sub
   
   

5. Press the F5 key to run the program.

6. Click on Command1. Note that the network adapter address is displayed in a message box.