At my work place, different computers are in different subnets, and if the PCs are in the same subnet as the Samba server, I can reach the file server by going to
\\myserv\MyFolder, but for the PC is in a different subnet, the only way for me to reach the server is by using IP
I am just wondering in VBA, if there is any way I can say:
if I can find the server using
\\myserv, then use
myserv, else use
Unfortunately I can not tweak the network at all and I want to set up this way so that at least when the IP changes, majority of my users could still use the tool by visiting
Assuming you are on Windows environment, here’s an alternative approach (without the actual code):
- In Excel VBA, use the SHELL function to execute a Net View function and send the output to a file. ie:
Dim vsFileName vsFileName = "C:\Temp\RandomFileName.txt" Shell("Net View \myServ > " & vsFileName )
- After that, check the filesize of the output. If output file size > 0, meaning the path is found. If the path cannot be found, the output filesize will be 0.
If FileLen( vsFileName ) = 0 Then vsNetworkPath = "188.8.131.52"
- Clean up after yourself by:
Kill( vsFileName )
This is an alternative if you don’t want to mess around with win32 functions. It’s a good idea to randomize the filename each time you run the code to avoid clashes.
Here is some code I use to check for server reachablility. It uses Windows winsock32 APIs and I haven’t had any problems with it. I don’t have to worry about privledges so I don’t know how it’d handle that.
I’ve commented the code a fair bit so hopefully you’ll understand whats going on should you need to tweak it. It with work as per the example sub I’ve used. I’ll let you do the code that sets the folder after the network path is checked 😉
This isn’t a trivial task but it’s a tricky problem so I’m happy to share the code. Start with the functions you’ll call to do the check – note how the paths are defined. I’ve tested these on my network and they all work, the Diskstation is checked by its network name and its IP:
Sub TestMyPaths() TestPath ("C:\") TestPath ("\Diskstation\") TestPath ("\192.168.99.5\") End Sub Sub TestPath(sServerName As String) If sServerName = "" Then Exit Sub If Not CheckPath(sServerName) Then MsgBox "Cannot find " & sServerName Else MsgBox "Found " & sServerName End If End Sub Private Function CheckPath(sfile As String) As Boolean 'Response Variables Dim bResponse As Boolean, bLocal As Boolean 'File System Variables Dim oFS As Object, oDrive As Object, oTemp As Object 'Variables for chkecing the server Dim strIPAddress As String, Reply As ICMP_ECHO_REPLY, lngSuccess As Long, sServer As String If sfile = "" Then Exit Function bResponse = False On Error GoTo SomeProblem ' Determine if drive is local and resolve all remote paths to UNC filenames Set oFS = CreateObject("Scripting.FileSystemObject") Set oDrive = oFS.Drives bLocal = False If UCase(VBA.Left(sfile, 1)) Like "[A-Z]" Then For Each oDrive In oFS.Drives If oDrive.Path = UCase(VBA.Left(sfile, 2)) Then If oDrive.DriveType = 3 Then ' Remote Drive sfile = Replace(sfile, (VBA.Left(sfile, 2)), oDrive.ShareName) Else bLocal = True End If Exit For End If Next oDrive End If If bLocal Then 'Allow for checking at the end of this if statement bResponse = True ElseIf VBA.Left(sfile, 1) <> "\" Then ' File Name only specified / Not a valid path bResponse = False Else 'Otherwise we are dealing with a server path 'Get the server name sServer = VBA.Mid$(sfile, 3, InStr(3, sfile, "\", vbTextCompare) - 3) 'Set up networking to check If SocketsInitialize() Then strIPAddress = GetIPFromHostName(sServer) 'Get the ipaddress of the server name lngSuccess = ping(strIPAddress, Reply) 'Ping the IP that is passing the address and get a reply. Call WSACleanup 'Clean up the sockets. If lngSuccess = 0 Then bResponse = True 'If we get a ping back we're all good End If End If SomeProblem: CheckPath = bResponse Set oTemp = Nothing Set oDrive = Nothing End Function
Then API declarations (these go at the top of your module).
#If Win64 Then Private Declare PtrSafe Function gethostbyname Lib "WSOCK32.DLL" (ByVal hostname As String) As Long Private Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (xDest As Any, xSource As Any, ByVal nbytes As Long) Private Declare PtrSafe Function WSAStartup Lib "WSOCK32.DLL" (ByVal wVersionRequired As Long, lpWSADATA As WSADATA) As Long Private Declare PtrSafe Function WSACleanup Lib "WSOCK32.DLL" () As Long #Else Private Declare Function gethostbyname Lib "WSOCK32.DLL" (ByVal hostname As String) As Long Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (xDest As Any, xSource As Any, ByVal nbytes As Long) Private Declare Function WSAStartup Lib "WSOCK32.DLL" (ByVal wVersionRequired As Long, lpWSADATA As WSADATA) As Long Private Declare Function WSACleanup Lib "WSOCK32.DLL" () As Long #End If 'NETWORK AND PING API FUNCTIONS #If Win64 Then Public Declare PtrSafe Function IcmpCreateFile Lib "icmp.dll" () As Long Public Declare PtrSafe Function inet_addr Lib "WSOCK32.DLL" (ByVal cp As String) As Long Public Declare PtrSafe Function IcmpCloseHandle Lib "icmp.dll" (ByVal IcmpHandle As Long) As Long Private Declare PtrSafe Function IcmpSendEcho Lib "icmp.dll" _ (ByVal IcmpHandle As Long, _ ByVal DestinationAddress As Long, _ ByVal RequestData As String, _ ByVal RequestSize As Long, _ ByVal RequestOptions As Long, _ ReplyBuffer As ICMP_ECHO_REPLY, _ ByVal ReplySize As Long, _ ByVal Timeout As Long) As Long #Else Public Declare Function IcmpCreateFile Lib "icmp.dll" () As Long Public Declare Function inet_addr Lib "WSOCK32.DLL" (ByVal cp As String) As Long Public Declare Function IcmpCloseHandle Lib "icmp.dll" (ByVal IcmpHandle As Long) As Long Private Declare Function IcmpSendEcho Lib "icmp.dll" _ (ByVal IcmpHandle As Long, _ ByVal DestinationAddress As Long, _ ByVal RequestData As String, _ ByVal RequestSize As Long, _ ByVal RequestOptions As Long, _ ReplyBuffer As ICMP_ECHO_REPLY, _ ByVal ReplySize As Long, _ ByVal Timeout As Long) As Long #End If Public Const WINSOCK_ERROR = "Windows Sockets not responding correctly." Public Const INADDR_NONE As Long = &HFFFFFFFF Public Const WSA_SUCCESS = 0 Public Const GWL_STYLE = -16 Public Const WS_SYSMENU = &H80000 Private Const ICMP_SUCCESS As Long = 0 Private Const WS_VERSION_REQD As Long = &H101 Private Const MAX_WSADescription As Long = 256 Private Const MAX_WSASYSStatus As Long = 128 'PING AND NETWORK ENUMS Private Type IP_OPTION_INFORMATION Ttl As Byte Tos As Byte Flags As Byte OptionsSize As Byte OptionsData As Long End Type Public Type ICMP_ECHO_REPLY Address As Long Status As Long RoundTripTime As Long DataSize As Long Reserved As Integer ptrData As Long Options As IP_OPTION_INFORMATION data As String * 250 End Type Private Type WSADATA wVersion As Integer wHighVersion As Integer szDescription(0 To MAX_WSADescription) As Byte szSystemStatus(0 To MAX_WSASYSStatus) As Byte wMaxSockets As Long wMaxUDPDG As Long dwVendorInfo As Long End Type
And then the generic network functions:
Public Function GetIPFromHostName(ByVal sHostName As String) As String 'converts a host name to an IP address. Dim ptrHosent As Long 'address of hostent structure Dim ptrName As Long 'address of name pointer Dim ptrAddress As Long 'address of address pointer Dim ptrIPAddress As Long Dim sAddress As String sAddress = Space$(4) ptrHosent = gethostbyname(sHostName & vbNullChar) If ptrHosent <> 0 Then ptrName = ptrHosent ptrAddress = ptrHosent + 12 'get the IP address CopyMemory ptrName, ByVal ptrName, 4 CopyMemory ptrAddress, ByVal ptrAddress, 4 CopyMemory ptrIPAddress, ByVal ptrAddress, 4 CopyMemory ByVal sAddress, ByVal ptrIPAddress, 4 GetIPFromHostName = IPToText(sAddress) End If End Function Private Function IPToText(ByVal IPAddress As String) As String IPToText = CStr(Asc(IPAddress)) & "." & _ CStr(Asc(Mid$(IPAddress, 2, 1))) & "." & _ CStr(Asc(Mid$(IPAddress, 3, 1))) & "." & _ CStr(Asc(Mid$(IPAddress, 4, 1))) End Function Public Function SocketsInitialize() As Boolean Dim WSAD As WSADATA SocketsInitialize = WSAStartup(WS_VERSION_REQD, WSAD) = ICMP_SUCCESS End Function Public Function ping(sAddress As String, Reply As ICMP_ECHO_REPLY) As Long 'Function to ping an address and see if a response is obtained Dim hIcmp As Long, lAddress As Long, lTimeOut As Long, StringToSend As String StringToSend = "test" 'Short string of data to send lTimeOut = 1000 'ms 'ICMP (ping) timeout lAddress = inet_addr(sAddress) 'Convert string address to a long representation 'If we have a valid response If (lAddress <> -1) And (lAddress <> 0) Then 'Create the handle for ICMP requests. hIcmp = IcmpCreateFile() If hIcmp Then 'Ping the destination IP address. Call IcmpSendEcho(hIcmp, lAddress, StringToSend, Len(StringToSend), 0, Reply, Len(Reply), lTimeOut) 'Reply status ping = Reply.Status 'Close the Icmp handle. IcmpCloseHandle hIcmp Else Debug.Print "failure opening icmp handle." ping = -1 End If Else ping = -1 End If End Function