Dapatkan Nama Host dari IP Address

Kode berikut berfungis untuk mendapatkan HostName dari IP Address, dengan fungsi yang ada di wsock32.

Berikut kodingnya :

Option Explicit

Private Const WSADescription_Len As Long = 256
Private Const WSASYS_Status_Len As Long = 128
Private Const WS_VERSION_REQD As Long = &H101
Private Const IP_SUCCESS As Long = 0
Private Const SOCKET_ERROR As Long = -1
Private Const AF_INET As Long = 2

Private Type WSADATA
wVersion As Integer
wHighVersion As Integer
szDescription(0 To WSADescription_Len) As Byte
szSystemStatus(0 To WSASYS_Status_Len) As Byte
imaxsockets As Integer
imaxudp As Integer
lpszvenderinfo As Long
End Type

Private Declare Function WSAStartup Lib "wsock32" _
(ByVal VersionReq As Long, _
WSADataReturn As WSADATA) As Long

Private Declare Function WSACleanup Lib "wsock32" () As Long

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

Private Declare Function gethostbyaddr Lib "wsock32" _
(haddr As Long, _
ByVal hnlen As Long, _
ByVal addrtype As Long) As Long

Private Declare Sub CopyMemory Lib "kernel32" _
Alias "RtlMoveMemory" _
(xDest As Any, _
xSource As Any, _
ByVal nbytes As Long)

Private Declare Function lstrlen Lib "kernel32" _
Alias "lstrlenA" _
(lpString As Any) As Long

Private Function SocketsInitialize() As Boolean
Dim WSAD As WSADATA
SocketsInitialize = WSAStartup(WS_VERSION_REQD, WSAD) = IP_SUCCESS
End Function

Private Sub SocketsCleanup()
If WSACleanup() <> 0 Then
MsgBox "Windows Sockets error occurred in Cleanup.", _
vbExclamation
End If
End Sub

Private Function GetHostNameFromIP(ByVal sAddress As String) As String

Dim ptrHosent As Long
Dim hAddress As Long
Dim nbytes As Long
If SocketsInitialize() Then
hAddress = inet_addr(sAddress)
If hAddress <> SOCKET_ERROR Then
ptrHosent = gethostbyaddr(hAddress, 4, AF_INET)
If ptrHosent <> 0 Then
CopyMemory ptrHosent, ByVal ptrHosent, 4
nbytes = lstrlen(ByVal ptrHosent)
If nbytes > 0 Then
sAddress = Space$(nbytes)
CopyMemory ByVal sAddress, ByVal ptrHosent, nbytes
GetHostNameFromIP = sAddress
End If

Else
MsgBox "memanggil gethostbyaddr gagal."
End If 'If ptrHosent
SocketsCleanup
Else
MsgBox "IP Address salah."
End If 'If hAddress
Else
MsgBox "Sockets failed to initialize."
End If 'If SocketsInitialize
End Function

Private Sub Form_Load()
MsgBox "HostName: " & GetHostNameFromIP("192.168.0.1")
End Sub