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Visual Basic Internet Routines IcmpSendEcho: Ping a Machine by Host Name |
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Posted: | Wed March 23, 2000 |
Updated: | Monday December 26, 2011 |
Applies to: | VB4-32, VB5, VB6 |
Developed with: | VB6, Windows NT4 |
OS restrictions: | None |
Author: | VBnet - Randy Birch, MSDN |
Related: |
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 |
Prerequisites |
Network or DUN connection. |
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When
only the name of a host is available, it is still possible to ping the server using Visual Basic. This routine, unlike the original Ping
method, does work with named domains. Here we utilize the Winsock gethostbyname API to resolve the host name to its IP address, then call the
ping method used for numerical IP addresses.
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. To test this application, you must be connected to a network or to your ISP via dial up networking (DUN). The basic code was translated from C descriptions in the MSDN. |
BAS Module Code |
None. |
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Form Code |
To a form add a command button (Command1), three text boxes at the top of the form (Text1, Text2, Text3) and six text boxes in a control array (Text4(0) - Text4(5)). Labels as desired.. Add the following to the form: |
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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 = (IP_STATUS_BASE + 1) Private Const IP_DEST_NET_UNREACHABLE As Long = (IP_STATUS_BASE + 2) Private Const IP_DEST_HOST_UNREACHABLE As Long = (IP_STATUS_BASE + 3) Private Const IP_DEST_PROT_UNREACHABLE As Long = (IP_STATUS_BASE + 4) Private Const IP_DEST_PORT_UNREACHABLE As Long = (IP_STATUS_BASE + 5) Private Const IP_NO_RESOURCES As Long = (IP_STATUS_BASE + 6) Private Const IP_BAD_OPTION As Long = (IP_STATUS_BASE + 7) Private Const IP_HW_ERROR As Long = (IP_STATUS_BASE + 8) Private Const IP_PACKET_TOO_BIG As Long = (IP_STATUS_BASE + 9) Private Const IP_REQ_TIMED_OUT As Long = (IP_STATUS_BASE + 10) Private Const IP_BAD_REQ As Long = (IP_STATUS_BASE + 11) Private Const IP_BAD_ROUTE As Long = (IP_STATUS_BASE + 12) Private Const IP_TTL_EXPIRED_TRANSIT As Long = (IP_STATUS_BASE + 13) Private Const IP_TTL_EXPIRED_REASSEM As Long = (IP_STATUS_BASE + 14) Private Const IP_PARAM_PROBLEM As Long = (IP_STATUS_BASE + 15) Private Const IP_SOURCE_QUENCH As Long = (IP_STATUS_BASE + 16) Private Const IP_OPTION_TOO_BIG As Long = (IP_STATUS_BASE + 17) Private Const IP_BAD_DESTINATION As Long = (IP_STATUS_BASE + 18) Private Const IP_ADDR_DELETED As Long = (IP_STATUS_BASE + 19) Private Const IP_SPEC_MTU_CHANGE As Long = (IP_STATUS_BASE + 20) Private Const IP_MTU_CHANGE As Long = (IP_STATUS_BASE + 21) Private Const IP_UNLOAD As Long = (IP_STATUS_BASE + 22) Private Const IP_ADDR_ADDED As Long = (IP_STATUS_BASE + 23) Private Const IP_GENERAL_FAILURE As Long = (IP_STATUS_BASE + 50) Private Const MAX_IP_STATUS As Long = (IP_STATUS_BASE + 50) Private Const IP_PENDING As Long = (IP_STATUS_BASE + 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 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 Type ICMP_OPTIONS Ttl As Byte Tos As Byte Flags As Byte OptionsSize As Byte OptionsData As Long End Type Private Type ICMP_ECHO_REPLY Address As Long status As Long RoundTripTime As Long DataSize As Long 'Reserved As Integer DataPointer As Long Options As ICMP_OPTIONS Data As String * 250 End Type Private Declare Function gethostbyname Lib "wsock32" _ (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 lstrlenA Lib "kernel32" _ (lpString As Any) As Long Private Declare Function WSAStartup Lib "wsock32" _ (ByVal wVersionRequired As Long, _ lpWSADATA As WSADATA) As Long Private Declare Function WSACleanup Lib "wsock32" () As Long 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 inet_addr Lib "wsock32" _ (ByVal s As String) As Long Private Declare Function inet_ntoa Lib "wsock32.dll" _ (ByVal addr As Long) As Long Private Declare Function lstrcpyA Lib "kernel32" _ (ByVal RetVal As String, _ ByVal Ptr As Long) As Long Private Sub Form_Load() Text1.Text = "www.yahoo.com" Text2.Text = "" Text3.Text = "Echo this" End Sub Private Sub Command1_Click() Dim ECHO As ICMP_ECHO_REPLY Dim pos As Long Dim success As Long Dim sIPAddress As String If SocketsInitialize() Then 'convert the host name into an IP address sIPAddress = GetIPFromHostName(Text1.Text) Text2.Text = sIPAddress 'ping the ip passing the address, text 'to use, and the ECHO structure success = Ping(sIPAddress, (Text3.Text), ECHO) 'display the results Text4(0).Text = GetStatusCode(success) Text4(1).Text = ECHO.Address Text4(2).Text = ECHO.RoundTripTime & " ms" Text4(3).Text = ECHO.DataSize & " bytes" If Left$(ECHO.Data, 1) <> Chr$(0) Then pos = InStr(ECHO.Data, Chr$(0)) Text4(4).Text = Left$(ECHO.Data, pos - 1) End If Text4(5).Text = ECHO.DataPointer SocketsCleanup Else MsgBox "Windows Sockets for 32 bit Windows " & _ "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 dwAddress is valid 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), _ PING_TIMEOUT) 'return the status as ping success Ping = ECHO.status 'close the port handle Call IcmpCloseHandle(hPort) End If 'If hPort Else 'the address format was probably invalid Ping = INADDR_NONE End If 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 Private Function GetIPFromHostName(ByVal sHostName As String) As String 'converts a host name to an IP address Dim ptrHosent As Long 'address of HOSENT structure Dim ptrName As Long 'address of name pointer Dim ptrAddress As Long 'address of address pointer Dim ptrIPAddress As Long Dim ptrIPAddress2 As Long ptrHosent = gethostbyname(sHostName & vbNullChar) If ptrHosent <> 0 Then 'assign pointer addresses and offset 'ptrName is the official name of the host (PC). 'If using the DNS or similar resolution system, 'it is the Fully Qualified Domain Name (FQDN) 'that caused the server to return a reply. 'If using a local hosts file, it is the first 'entry after the IP address. ptrName = ptrHosent 'Null-terminated list of addresses for the host. 'The Address is offset 12 bytes from the start of 'the HOSENT structure. Note: Here we are retrieving 'only the first address returned. To return more than 'one, define sAddress as a string array and loop through 'the 4-byte ptrIPAddress members returned. The last 'item is a terminating null. All addresses are returned 'in network byte order. ptrAddress = ptrHosent + 12 'get the IP address CopyMemory ptrName, ByVal ptrName, 4 CopyMemory ptrAddress, ByVal ptrAddress, 4 CopyMemory ptrIPAddress, ByVal ptrAddress, 4 CopyMemory ptrIPAddress2, ByVal ptrIPAddress, 4 GetIPFromHostName = GetInetStrFromPtr(ptrIPAddress2) End If End Function Private Function GetStrFromPtrA(ByVal lpszA As Long) As String GetStrFromPtrA = String$(lstrlenA(ByVal lpszA), 0) Call lstrcpyA(ByVal GetStrFromPtrA, ByVal lpszA) End Function Private Function GetInetStrFromPtr(Address As Long) As String GetInetStrFromPtr = GetStrFromPtrA(inet_ntoa(Address)) 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 Dim WSAD As WSADATA SocketsInitialize = WSAStartup(WS_VERSION_REQD, WSAD) = IP_SUCCESS End Function |
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Copyright ©1996-2011 VBnet and Randy Birch. All Rights Reserved. |