by SERRANA (3 Submissions)
Category: Internet/HTML
Compatability: Visual Basic 5.0
Difficulty: Unknown Difficulty
Originally Published: Sat 30th July 2005
Date Added: Mon 8th February 2021
Rating: 
(1 Votes)
Retrieve a remote MAC Address
VBcoders
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 SrcIP As Long, _
pMacAddr As Long, _
PhyAddrLen As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" _
Alias "RtlMoveMemory" _
(dst As Any, _
src As Any, _
ByVal bcount As Long)
Private Sub Form_Load()
Text1.Text = "192.168.1.101"
Text2.Text = ""
Command1.Caption = "Get Remote Mac Address"
End Sub
Private Sub Command1_Click()
Dim sRemoteMacAddress As String
If Len(Text1.Text) > 0 Then
If GetRemoteMACAddress(Text1.Text, sRemoteMacAddress) Then
Text2.Text = sRemoteMacAddress
Else
Text2.Text = "(SendARP call failed)"
End If
End If
End Sub
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
'convert the string IP into
'an unsigned long value containing
'a suitable binary representation
'of the Internet address given
dwRemoteIP = inet_addr(sRemoteIP)
If dwRemoteIP <> 0 Then
'set PhyAddrLen to 6
PhyAddrLen = 6
'retrieve the remote MAC address
If SendARP(dwRemoteIP, 0&, pMacAddr, PhyAddrLen) = NO_ERROR Then
If pMacAddr <> 0 And PhyAddrLen <> 0 Then
'returned value is a long pointer
'to the mac address, so copy data
'to a byte array
ReDim bpMacAddr(0 To PhyAddrLen - 1)
CopyMemory bpMacAddr(0), pMacAddr, ByVal PhyAddrLen
'loop through array to build string
For cnt = 0 To PhyAddrLen - 1
If bpMacAddr(cnt) = 0 Then
tmp = tmp & "00-"
Else
tmp = tmp & Hex$(bpMacAddr(cnt)) & "-"
End If
Next
'remove the trailing dash
'added above and return True
If Len(tmp) > 0 Then
sRemoteMacAddress = Left$(tmp, Len(tmp) - 1)
GetRemoteMACAddress = True
End If
Exit Function
Else
GetRemoteMACAddress = False
End If
Else
GetRemoteMACAddress = False
End If 'SendARP
Else
GetRemoteMACAddress = False
End If 'dwRemoteIP
End Function