Visual Basic Internet Routines

IcmpSendEcho: Ping a Machine by IP Address
Posted:   Friday August 21, 1998
Updated:   Monday December 26, 2011
Applies to:   VB4-32, VB5, VB6
Developed with:   VB6, Windows NT4
OS restrictions:   None
Author:   VBnet - Randy Birch, Unknown source


Netbios: Determine Local Adapter MAC Address
SendARP: Determine Local or Remote Adapter MAC Addresses
gethostbyname: Determine Network Host Name and IP Address
Netbios: Determine Local Adapter MAC Addresses through LANA Enumeration
gethostbyaddr: Obtain Host Name from IP Address
IcmpSendEcho: Ping a Machine by IP Address
IcmpSendEcho: Ping a Machine by Host Name

URLDownloadToFile: Obtain Machine's Public IP Behind Router
IcmpSendEcho: Perform a Tracert (Trace Route) in VB with Host Name Resolution
Network or DUN connection.

With Visual Basic applications expanding more into the enterprise, basic networking functionality often needs to be duplicated by the application. Using the routine here, you will be able to ping any IP address passed.

Ping is a tool that helps to verify IP-level connectivity. When troubleshooting, the ping command is used to send an ICMP echo request to a target host name or IP address. Use ping whenever you need to verify that a host computer can connect to the TCP/IP network and network resources. You can also use the ping utility to isolate network hardware problems and incompatible configurations.

It is usually best to verify that a route exists between the local computer and a network host by first using ping and the IP address of the network host to which you want to connect. First try pinging the IP address of the target host to see if it will respond, because this is the simplest case.

The concept in the VB implementation is to pass to a routine the address to ping, and a message under 32 bytes that the ping should return if successful. This routine does not worked with named domains; it only works when passed the numerical address itself.

To test this application, you must be connected to a network or to your ISP via dial up networking (DUN).

I do not profess to know anything at all about networking or internet functions ... this code  (as a bas file only) was provided to me unsigned. If the author is known, I'd appreciate hearing from them so proper credit can be given. Furthermore, it is commented only as far as the author did, with a bit of MSDN descriptions thrown in.

Finally, just to keep the error message lines short (narrow), I've split them into multiple lines as needed.

 BAS Module Code

 Form Code
To a form add a command button (Command1), two text boxes (Text1, Text2) to the top of the form, and six text boxes in a control array (Text3(0) - Text3(5)) below. The labels provide information only and are not required to run the demo. Add the following to the form:

Option Explicit
' Copyright 1996-2011 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 IP_SUCCESS As Long = 0
Private Const IP_STATUS_BASE As Long = 11000
Private Const IP_BUF_TOO_SMALL As Long = (11000 + 1)
Private Const IP_DEST_NET_UNREACHABLE As Long = (11000 + 2)
Private Const IP_DEST_HOST_UNREACHABLE As Long = (11000 + 3)
Private Const IP_DEST_PROT_UNREACHABLE As Long = (11000 + 4)
Private Const IP_DEST_PORT_UNREACHABLE As Long = (11000 + 5)
Private Const IP_NO_RESOURCES As Long = (11000 + 6)
Private Const IP_BAD_OPTION As Long = (11000 + 7)
Private Const IP_HW_ERROR As Long = (11000 + 8)
Private Const IP_PACKET_TOO_BIG As Long = (11000 + 9)
Private Const IP_REQ_TIMED_OUT As Long = (11000 + 10)
Private Const IP_BAD_REQ As Long = (11000 + 11)
Private Const IP_BAD_ROUTE As Long = (11000 + 12)
Private Const IP_TTL_EXPIRED_TRANSIT As Long = (11000 + 13)
Private Const IP_TTL_EXPIRED_REASSEM As Long = (11000 + 14)
Private Const IP_PARAM_PROBLEM As Long = (11000 + 15)
Private Const IP_SOURCE_QUENCH As Long = (11000 + 16)
Private Const IP_OPTION_TOO_BIG As Long = (11000 + 17)
Private Const IP_BAD_DESTINATION As Long = (11000 + 18)
Private Const IP_ADDR_DELETED As Long = (11000 + 19)
Private Const IP_SPEC_MTU_CHANGE As Long = (11000 + 20)
Private Const IP_MTU_CHANGE As Long = (11000 + 21)
Private Const IP_UNLOAD As Long = (11000 + 22)
Private Const IP_ADDR_ADDED As Long = (11000 + 23)
Private Const IP_GENERAL_FAILURE As Long = (11000 + 50)
Private Const MAX_IP_STATUS As Long = (11000 + 50)
Private Const IP_PENDING As Long = (11000 + 255)
Private Const PING_TIMEOUT As Long = 500
Private Const WS_VERSION_REQD As Long = &H101
Private Const MIN_SOCKETS_REQD As Long = 1
Private Const SOCKET_ERROR As Long = -1
Private Const INADDR_NONE As Long = &HFFFFFFFF
Private Const MAX_WSADescription As Long = 256
Private Const MAX_WSASYSStatus As Long = 128

    Ttl             As Byte
    Tos             As Byte
    Flags           As Byte
    OptionsSize     As Byte
    OptionsData     As Long
End Type

    Address         As Long
    status          As Long
    RoundTripTime   As Long
    DataSize        As Long 'formerly integer
   'Reserved        As Integer
    DataPointer     As Long
    Options         As ICMP_OPTIONS
    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

Private Declare Function IcmpCreateFile Lib "icmp.dll" () As Long

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

Private Declare Function WSAStartup Lib "wsock32" _
   (ByVal wVersionRequired As Long, _
Private Declare Function WSACleanup Lib "wsock32" () As Long

Private Declare Function gethostname Lib "wsock32" _
   (ByVal szHost As String, _
    ByVal dwHostLen As Long) As Long
Private Declare Function gethostbyname Lib "wsock32" _
   (ByVal szHost 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 inet_addr Lib "wsock32" _
   (ByVal s As String) As Long

Private Sub Command1_Click()
   Dim pos As Long
   Dim success As Long
   If SocketsInitialize() Then
     'ping the IP by passing the address,
     'text to send, and the ECHO structure.
      success = Ping((Text1.Text), (Text2.Text), ECHO)
     'display the results
      Text3(0).Text = GetStatusCode(success)
      Text3(1).Text = ECHO.Address
      Text3(2).Text = ECHO.RoundTripTime & " ms"
      Text3(3).Text = ECHO.DataSize & " bytes"
      If Left$(ECHO.Data, 1) <> Chr$(0) Then
         pos = InStr(ECHO.Data, Chr$(0))
         Text3(4).Text = Left$(ECHO.Data, pos - 1)
      End If
      Text3(5).Text = ECHO.DataPointer
        MsgBox "Windows Sockets for 32 bit Windows " & _
               "environments is not successfully responding."
   End If
End Sub

Private Function Ping(sAddress As String, _
                     sDataToSend As String, _
                     ECHO As ICMP_ECHO_REPLY) As Long

  'If Ping succeeds :
  '.RoundTripTime = time in ms for the ping to complete,
  '.Data is the data returned (NULL terminated)
  '.Address is the Ip address that actually replied
  '.DataSize is the size of the string in .Data
  '.Status will be 0
  'If Ping fails .Status will be the error code
   Dim hPort As Long
   Dim dwAddress As Long
  'convert the address into a long representation
   dwAddress = inet_addr(sAddress)
  'if a valid address..
   If dwAddress <> INADDR_NONE Then
     'open a port
      hPort = IcmpCreateFile()
     'and if successful,
      If hPort Then
        'ping it.
         Call IcmpSendEcho(hPort, _
                           dwAddress, _
                           sDataToSend, _
                           Len(sDataToSend), _
                           0, _
                           ECHO, _
                           Len(ECHO), _

        'return the status as ping succes and close
         Ping = ECHO.status
         Call IcmpCloseHandle(hPort)
      End If  
        'the address format was probably invalid
         Ping = INADDR_NONE
   End If
End Function

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

Private Function SocketsInitialize() As Boolean

   SocketsInitialize = WSAStartup(WS_VERSION_REQD, WSAD) = IP_SUCCESS
End Function

Private Function GetStatusCode(status As Long) As String

   Dim msg As String
   Select Case status
      Case IP_SUCCESS:               msg = "ip success"
      Case INADDR_NONE:              msg = "inet_addr: bad IP format"
      Case IP_BUF_TOO_SMALL:         msg = "ip buf too_small"
      Case IP_DEST_NET_UNREACHABLE:  msg = "ip dest net unreachable"
      Case IP_DEST_HOST_UNREACHABLE: msg = "ip dest host unreachable"
      Case IP_DEST_PROT_UNREACHABLE: msg = "ip dest prot unreachable"
      Case IP_DEST_PORT_UNREACHABLE: msg = "ip dest port unreachable"
      Case IP_NO_RESOURCES:          msg = "ip no resources"
      Case IP_BAD_OPTION:            msg = "ip bad option"
      Case IP_HW_ERROR:              msg = "ip hw_error"
      Case IP_PACKET_TOO_BIG:        msg = "ip packet too_big"
      Case IP_REQ_TIMED_OUT:         msg = "ip req timed out"
      Case IP_BAD_REQ:               msg = "ip bad req"
      Case IP_BAD_ROUTE:             msg = "ip bad route"
      Case IP_TTL_EXPIRED_TRANSIT:   msg = "ip ttl expired transit"
      Case IP_TTL_EXPIRED_REASSEM:   msg = "ip ttl expired reassem"
      Case IP_PARAM_PROBLEM:         msg = "ip param_problem"
      Case IP_SOURCE_QUENCH:         msg = "ip source quench"
      Case IP_OPTION_TOO_BIG:        msg = "ip option too_big"
      Case IP_BAD_DESTINATION:       msg = "ip bad destination"
      Case IP_ADDR_DELETED:          msg = "ip addr deleted"
      Case IP_SPEC_MTU_CHANGE:       msg = "ip spec mtu change"
      Case IP_MTU_CHANGE:            msg = "ip mtu_change"
      Case IP_UNLOAD:                msg = "ip unload"
      Case IP_ADDR_ADDED:            msg = "ip addr added"
      Case IP_GENERAL_FAILURE:       msg = "ip general failure"
      Case IP_PENDING:               msg = "ip pending"
      Case PING_TIMEOUT:             msg = "ping timeout"
      Case Else:                     msg = "unknown  msg returned"
   End Select
   GetStatusCode = CStr(status) & "   [ " & msg & " ]"
End Function


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Copyright 1996-2011 VBnet and Randy Birch. All Rights Reserved.
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