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isnoend2001
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Ping a website and check internet connection

i have created a function that runs on my desktop that checks my website is up every 1/2 hour
The ping works very fast,and pouts the results in a listbox but now i want to check to be sure my internet connection is valid before the ping.The problem I have run into is the checking the internet connection takes a couple seconds.
 How can i make the ping wait until the internet connection is done and results entered into a list box ?
Visual Basic Classic

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SStory

8/22/2022 - Mon
SStory

Something like this should work:

Module Module1
    'add as many known sites as you wish; those that are pingable if the internet is up
    Private InternetSites() As String = {"www.foxnews.com", "www.google.com", "www.yahoo.com", "www.expedia.com"}
    Const MAX_FAILURES_TO_PROVE_DOWN As Byte = 3

    Sub Main()
        If My.Computer.Network.IsAvailable Then
            If InternetIsReachable() Then
                'DO YOUR STUFF HERE
            End If
        End If
    End Sub

    Private Function InternetIsReachable() As Boolean
        Dim FailureCount As Short = 0

        For Each Site As String In InternetSites
            If My.Computer.Network.Ping(Site) Then
                Return True
            Else
                FailureCount += 1
            End If

            If FailureCount > MAX_FAILURES_TO_PROVE_DOWN Then
                Return False
            End If
        Next

        Return False
    End Function
End Module

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I haven't tested it yet and you'll need to use it from a Win form if you want a listbox.
isnoend2001

ASKER
thanks  SStory
Don't need code to check the connection. only to wait until the check is done before the ping
SStory

My code will not return for your ping until it has checked.
I don't see the problem. You call it and it will try and try and until it gives a pass or fail. If it passes you can ping.
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James Murphy
isnoend2001

ASKER
I want to know why the Ping has failed.
If i unplug from the internet and check if connected it takes a few seconds to time out
During that time it tries to ping which fails. Then I cannot determine why the ping fails.

I am testing some other code now:

While mConnectionCheckDone = False
  DoEvents
    DoEvents
    Sleep (55)
Wend
mConnectionCheckDone = False
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SStory

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isnoend2001

ASKER
Thanks
SStory

Other good ideas here.
http://stackoverflow.com/questions/1085045/check-whether-internet-connection-is-available-with-c-sharp

DNS lookup, then download a known txt file.

As to where it fails you would need to do a tracert

That means see if your LAN interface is up, then ping LAN side of your router(s) and each hop until you ping a website.  Wherever it fails is where to look.
Basically ICMP protocol.
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