LanCardAddress - Read the Ethernet address of a LAN card

Const NCBNAMSZ = 16

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
    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(10) As NAME_BUFFER
End Type

Private Declare Function Netbios Lib "netapi32.dll" (pncb As NCB) As Byte

' Read the Ethernet address of a LAN card.
' This number can be considered to uniquely identify a network adapter

Private Function LanCardAddress(ByVal cardNum As Long) As String
    Dim ncbInfo As NCB
    Dim astatInfo As ASTAT
    Dim i As Integer
    
    Const NCBASTAT = &H33
    Const NCBRESET = &H32
    
    'Reset the card
    ncbInfo.ncb_command = NCBRESET
    Netbios ncbInfo
    
    ' Get info from the card
    ncbInfo.ncb_command = NCBASTAT
    ncbInfo.ncb_lana_num = cardNum
    ncbInfo.ncb_callname = "* "
    ncbInfo.ncb_length = Len(astatInfo)
    ' prepare the address where the result is to be delivered
    ncbInfo.ncb_buffer = VarPtr(astatInfo)
    Netbios ncbInfo
    
    ' read the result
    For i = 0 To 5
        LanCardAddress = LanCardAddress & Right$("00" & Hex$ _
            (astatInfo.adapt.adapter_address(i)), 2)
    Next
    
End Function