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Chip Pearson Chip Pearson is offline
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Posts: 7,247
Default IP address to Hostname in Excel

Nice code. Randy Birch's site is a treasure trove. One thing caught my
eye, though.

szDescription(0 To WSADescription_Len) As Byte
szSystemStatus(0 To WSASYS_Status_Len) As Byte


Since these are 0-based arrays, shouldn't you subtract 1 from the _Len
variables? E.g.,

szDescription(0 To WSADescription_Len - 1) As Byte
szSystemStatus(0 To WSASYS_Status_Len - 1) As Byte

Cordially,
Chip Pearson
Microsoft Most Valuable Professional,
Excel, 1998 - 2010
Pearson Software Consulting, LLC
www.cpearson.com


On Sun, 11 Apr 2010 14:10:11 +0000, joel
wrote:


I found code on the web that works fine. I added a routing at the end
to test the code.


''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''
' Copyright ©1996-2009 VBnet, Randy Birch, All Rights Reserved.
' Some pages may also contain other copyrights by the author.
''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''
' Distribution: You can freely use this code in your own
' applications, but you may not reproduce
' or publish this code on any web site,
' online service, or distribute as source
' on any media without express permission.
''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''
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 Sub Command1_Click()

Text2.Text = GetHostNameFromIP(Text1.Text)

End Sub


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

'convert string address to long
hAddress = inet_addr(sAddress)

If hAddress < SOCKET_ERROR Then

'obtain a pointer to the HOSTENT structure
'that contains the name and address
'corresponding to the given network address.
ptrHosent = gethostbyaddr(hAddress, 4, AF_INET)

If ptrHosent < 0 Then

'convert address and
'get resolved hostname
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 "Call to gethostbyaddr failed."
End If 'If ptrHosent

SocketsCleanup

Else
MsgBox "String passed is an invalid IP."
End If 'If hAddress

Else
MsgBox "Sockets failed to initialize."
End If 'If SocketsInitialize

End Function

Sub test()
MsgBox (GetHostNameFromIP("192.168.1.30"))

End Sub