Option Explicit



Private Const No_ERROR = 0



Private Declare Function inet_addr Lib "wsock32.dll" (ByVal s As String) As Long

Private Declare Function SendARP Lib "iphlpapi.dll" (ByVal DestIp As Long, ByVal ScrIP As Long, pMacAddr As Long, PhyAddrLen As Long) As Long

Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (dst As Any, src As Any, ByVal bcount As Long)



Private Function GetRemoteMACAddress(ByVal sRemoteIP As String, sRemoteMacAddress As String) As Boolean

    Dim dwRemoteIp As Long

    Dim pMacAddr As Long

    Dim bpMacAddr() As Byte

    Dim PhyAddrLen As Long

    Dim cnt As Long

    Dim tmp As String

    

    dwRemoteIp = inet_addr(sRemoteIP)

    If dwRemoteIp <> 0 Then

        PhyAddrLen = 6

        If SendARP(dwRemoteIp, 0&, pMacAddr, PhyAddrLen) = No_ERROR Then

            If pMacAddr <> 0 And PhyAddrLen <> 0 Then

                ReDim bpMacAddr(0 To PhyAddrLen - 1)

                CopyMemory bpMacAddr(0), pMacAddr, ByVal PhyAddrLen

                For cnt = 0 To PhyAddrLen - 1

                    If bpMacAddr(cnt) = 0 Then

                        tmp = tmp & "00-"

                    Else

                        tmp = tmp & Hex$(bpMacAddr(cnt)) & "-"

                    End If

                Next

                

                If Len(tmp) > 0 Then

                    sRemoteMacAddress = Left$(tmp, Len(tmp) - 1)

                    GetRemoteMACAddress = True

                End If

                

                Exit Function

            Else

                GetRemoteMACAddress = False

            End If

        Else

            GetRemoteMACAddress = False

        End If

    Else

        GetRemoteMACAddress = False

    End If

End Function



Private Sub btnGetMac_Click()

Dim sRemoteMacAddress As String

If Len(txtIpAddress.Text) > 0 Then

    If GetRemoteMACAddress(txtIpAddress.Text, sRemoteMacAddress) Then

        lblMacAddress.Caption = sRemoteMacAddress

    Else

        lblMacAddress.Caption = "(SendARP call failed)"

    End If

End If

End Sub