how to ping from Windows Mobile application

[next1]

Hello,

I can't find a way to ping in VB.net 2008 from Windows mobile application. There are no namespaces like My.Computer.Network and System.Net.NetworkInformation, from where I usually use Ping and PingCompleted handler. Is there any easy way to check if some IP is online?

Thanks!

[petevick]

There is a ping class in the OpenNetCF or there is some code here using IcmpSendEcho2 that you could translate to VB

[next1]

Really thank you!

[next1]

Hi Petevick,

I successfully P/Invoke IcmpSendEcho2 and it's working almost perfect. But there are still two things that annoyed me. Here is the IcmpSendEcho2 DllImport:

    <DllImport("iphlpapi.dll", SetLastError:=True)> _
    Private Shared Function IcmpSendEcho2(ByVal icmpHandle As IntPtr, _
                                          ByVal hEvent As Int32, _
                                          ByVal ApcRoutine As Int32, _
                                          ByVal ApcContext As Int32, _
                                          ByVal destinationAddress As Int32, _
                                          ByVal requestData As String, _
                                          ByVal requestSize As Int32, _
                                          ByRef requestOptions As ICMP_OPTIONS, _
                                          ByRef replyBuffer As ICMP_ECHO_REPLY, _
                                          ByVal replySize As Int32, _
                                          ByVal timeout As Int32) As Int32

1. When the destination host is unknown or its offline, there is still too long time out using IcmpSendEcho2. Is there a way to solve it, using hEvent.. according to this:

This function sends an ICMP echo request and the call returns either immediately,
if the Event parameter is non-NULL

In my case, I use it as Int32 which is null because I don't really know how to implement it as EventHandler

2. The time for DNS is too long if it's not in my network (it's just hang for 5-6seconds). I use this to resolve the IP address, before I start pinging:

                Try
                    ipEntry = Net.Dns.GetHostEntry(DestinationHost.Text)
                    destinationIP = ipEntry.AddressList(0)
                Catch ex As Exception
                End Try

Can you please give me a hand in this with suggestion, or just point me in the right direction?

Thank you!

[petevick]

If you ping from your desktop, using command prompt, to a machine you know is offline, does it take shorter, longer or the same as your code?

[next1]

Well, my code is a little bit faster than cmd\ping command with the same timeout param (ping <ip> -w <timeout>). Is there a way IcmpSendEcho2 to work as it is described in MSDN: "This function sends an ICMP echo request and the call returns either immediately, if the Event parameter is non-NULL"?

Thank you Petevick!

[petevick]

This help?

[next1]

Hello Petevick,

That was the first place from where I start after you point me, but this example is for IcmpSendEcho and work only with timeouts. This was the reason I start to P/Invoke IcmpSendEcho2 but hang on creating the event parameter (2nd one) till now... I just P/Invoke the CreateEvent from coredll.dll and this do the trick

Providing the code for those who are looking for this:

Imports HANDLE = System.IntPtr

    <DllImport("coredll.dll", SetLastError:=True, CallingConvention:=CallingConvention.Winapi, CharSet:=CharSet.Auto)> _
    Public Shared Function CreateEvent(ByVal lpEventAttributes As HANDLE, <[In](), MarshalAs(UnmanagedType.Bool)> _
                                       ByVal bManualReset As Boolean, <[In](), MarshalAs(UnmanagedType.Bool)> _
                                       ByVal bIntialState As Boolean, <[In](), MarshalAs(UnmanagedType.BStr)> _
                                       ByVal lpName As String) As HANDLE
    End Function

Thanks again!

[next1]

The only thing that annoyed me is the DNS thingy:
The time for DNS is too long if it's not in my network. I use this to resolve the IP address, before I start pinging:

                Try
                    ipEntry = Net.Dns.GetHostEntry(DestinationHost.Text)
                    destinationIP = ipEntry.AddressList(0)
                Catch ex As Exception
                End Try

Is there a way to reduce the time for GetHostEntry?

Thanks!

[next1]

The only thing that annoyed me is the DNS thingy:
The time for DNS is too long if it's not in my network. I use this to resolve the IP address, before I start pinging:

                Try
                    ipEntry = Net.Dns.GetHostEntry(DestinationHost.Text)
                    destinationIP = ipEntry.AddressList(0)
                Catch ex As Exception
                End Try

Is there a way to reduce the time for GetHostEntry?

Thanks!

...or use some timeout for Net.Dns.GetHostEntry

Anyone?

[petevick]

Again - how long does it take if you do it from your desktop

Generally, you are not going to beat those times

[next1]

I don't want to beat that times, just want the same times.

From my PC: nslookup yahoo.com answer almost immediately (less then 1sek)

From my PPC(with the code above) ~3 seconds when I try it for the first time(after program start) and ~2 seconds after the 1st time... Both (PC and PPC) are connected to same router. Any idea?

[petevick]

Hi,
how long does that code take on the desktop?

[next1]

Guess the problem is in my PPC, because from my PC, the code above return almost immediately (less than 1 second)

[petevick]

Have you tried using VXUtil from www.cam.com to see what timings they get from your device - worth a shot, as you may be chasing something unattainable