Detecting if Dialup is active

[Scott Turchin]

I saw this somewhere but my search was fruitless ;(

I just want to know if the user is connected through his DUN (Dialup Networking)..
If he's not I want to sit tight, if he is, I go to work ...


Thanks


Scott


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Scott
mailto:[email protected][email protected]</A>

[Don Dickinson]

Download my RAS wrapper from www.basicguru.com/dickinson
There is code within that will enumerate the active RAS connections.
It will also Dial and Disconnect connections.

--Don

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www.basicguru.com/dickinson

[Edwin Knoppert]

+ On my site, in the helpfile(faq) is a topic, dialup...


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[Dave Navarro]

E.B.,

How about posting a URL... Thanks!

--Dave


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[Semen Matusovski]

In IE4 + there is a special function InternetGetConnectedState

#Compile Exe

Declare Function InternetGetConnectedState Lib "wininet.dll" Alias "InternetGetConnectedState" (lpdwFlags As Long, _
   ByVal dwReserved As Long) As Long

%INTERNET_CONNECTION_MODEM      = &H1&
%INTERNET_CONNECTION_LAN        = &H2&
%INTERNET_CONNECTION_PROXY      = &H4&
%INTERNET_CONNECTION_MODEM_BUSY = &H8&
%INTERNET_RAS_INSTALLED         = &H10&
%INTERNET_CONNECTION_OFFLINE    = &H20&
%INTERNET_CONNECTION_CONFIGURED = &H40&

Function PbMain
   Dim dwflags As Long
   InternetGetConnectedState dwflags, 0&
   MsgBox Hex$(dwFlags)
End Function

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[Edwin Knoppert]

My site is allways in my profile.
(In case my site name changes)




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[Scott Turchin]

I think that just might do it, I'm not so much concerned with the dialup, just with ANY connection, and that appears to do it.

if it comes back as 20 I assume it's failing ??? Otherwise it would appear to have a connection...

Scott

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Scott
mailto:[email protected][email protected]</A>

[Scott Turchin]

Would this be a safe assumption?

Function IsInternetAvailable() As Long
   Dim dwflags As Long
   InternetGetConnectedState dwflags, 0&
   Select Case dwFlags
          Case 1,2,4,8,10
               Function = %TRUE
          Case Else
               Function = %FALSE
   End Select
End Function

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Scott
mailto:[email protected][email protected]</A>

[Semen Matusovski]

You should test Return Value, not dwflags (I was interesting in type of connection)

InternetGetConnectedState Function

--------------------------------------------------------------------------------

Retrieves the connected state of the local system.

Syntax

BOOL InternetGetConnectedState(
OUT LPDWORD lpdwFlags,
IN DWORD dwReserved
);

Parameters

lpdwFlags
Address of an unsigned long integer variable where the connection description should be returned. This can be a combination of the following values:
INTERNET_CONNECTION_CONFIGURED
Local system has a valid connection to the Internet, but it may or may not be currently connected.
INTERNET_CONNECTION_LAN
Local system uses a local area network to connect to the Internet.
INTERNET_CONNECTION_MODEM
Local system uses a modem to connect to the Internet.
INTERNET_CONNECTION_MODEM_BUSY
No longer used.
INTERNET_CONNECTION_OFFLINE
Local system is in offline mode.
INTERNET_CONNECTION_PROXY
Local system uses a proxy server to connect to the Internet.
INTERNET_RAS_INSTALLED
Local system has RAS installed.
dwReserved
Reserved. Must be set to zero.

Return Value

Returns TRUE if there is an Internet connection, or FALSE otherwise.



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[Scott Turchin]

Ahhhhh I see the light!


Thanks, So I think the guy has a dialup, i tell it a dialup configured and test for it....(??)..
makes sense...

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Scott
mailto:[email protected][email protected]</A>

[Scott Turchin]

This seems to work rather nicely:

Function IsInternetAvailable() As Long
Dim dwflags     As Long
Dim lResult     As Long
%INTERNET_CONNECTION_OFFLINE    = &H20&


lResult = InternetGetConnectedState(dwflags, 0&)
If lResult = %INTERNET_CONNECTION_OFFLINE Then
   Function = %FALSE
Else
   Function = %TRUE
End If
End Function

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Scott
mailto:[email protected][email protected]</A>

[Peter Amick]

Scott,

I have had some experience using InternetGetConnectedState in a custom program for a client, and I have found that while it is a useful function, it is not reliable on its own for detecting an active connection.

Here's why:

First, as I recall it looks for the connection which has been set up as the default connection for the machine, which may or may not be the connection that the user ordinarily uses or is currently using.

Second, if the system uses a LAN to connect, this function may report an active connection even if the LAN is not currently connected to the net.

Third, if the system uses a modem, InternetGetConnectedState will report a connection even if the modem is in the process of dialing, or otherwise running but not connected.

If you're going to use this function, I would strongly suggest you do some further checking on the connection, as in the following pseudo-code:

Call InternetGetConnectedState

IF ConnectionMeathod = "Modem" THEN
    CALL rsActiveConnections and then rsGetConnectionStatus on any connections you find

ELSEIF ConnectionMeathod = "LAN" OR ConnectionMeathod = "Proxy Server" THEN
	hInet = InternetOpen(AppTitle, %INTERNET_OPEN_TYPE_PRECONFIG, zNull, zNull, 0&)
 	IF hInet THEN
    		Flags = %INTERNET_FLAG_KEEP_CONNECTION OR %INTERNET_FLAG_NO_CACHE_WRITE OR %INTERNET_FLAG_RELOAD
          hUrl = InternetOpenUrl(hInet, zURL, zNull, 0, Flags, 0)
          IF hUrl THEN
            ConnectionActive = %True
          ELSE
                ConnectionActive = %False
         	END IF
         	CALL InternetCloseHandle(hInet)
    	End If
END IF

Originally posted by Scott Turchin:
This seems to work rather nicely:

Function IsInternetAvailable() As Long
Dim dwflags     As Long
Dim lResult     As Long
%INTERNET_CONNECTION_OFFLINE    = &H20&


lResult = InternetGetConnectedState(dwflags, 0&)
If lResult = %INTERNET_CONNECTION_OFFLINE Then
   Function = %FALSE
Else
   Function = %TRUE
End If
End Function

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Peter Amick
Baybuild Solutions

[Peter Amick]

Scott,

I just picked up this article from the knowledge base:

SUMMARY
Many of you want to know if a computer has an active Internet connection before trying to connect to the Internet using the WinInet API or some other communication interface. The internet connection is important if you don't want your application to cause Windows to automatically dial the default Internet modem connection.
This article provides a mechanism for determining if an Internet site is accessible without the risk of you being prompted to dial into another Internet Service Provider.
MORE INFORMATION
Usually the best way to determine if you have a connection to a particular computer is to attempt the connection. If the autodial feature of Windows is enabled then attempting the connection may cause the default Internet dialup connectoid to be opened, and you will be prompted with your credentials to connect.
To avoid having the default Internet connectoid dialed, the InternetGetConnectedState function can be used to determine if there is a default Internet dialup connectoid configured and whether it is currently active or not. If there is a default Internet dialup connectoid configured and it is not currently active then InternetGetConnectedState will return FALSE. If InternetGetConnectedState returns TRUE then you can attempt to connect to the Internet resource without fear of being prompted to connect to another Internet Service Provider.
The following code demonstrates how you would do this:

if (InternetGetConnectedState(...) == FALSE)
{
    // Don't attempt connection or it will bring up the dialog
    ...
}
else
{
    //Attempt connection
    if (InternetOpenURL(...) == NULL)
    {
        // Call failed
        err = GetLastError();
        if ((err == ERROR_INTERNET_NAME_NOT_RESOLVED) | |
            (err == ERROR_INTERNET_CANNOT_CONNECT) | |
            (err == ERROR_INTERNET_TIMEOUT))
        {
            // probably not connected...handle appropriately
            ...
        }
    }
    // We're connected!!!
    ....
}

You cannot rely solely on the fact that InternetGetConnectedState returning TRUE means that you have a valid active Internet connection. It is impossible for InternetGetConnectedState to determine if the entire connection to the Internet is functioning without sending a request to a server. This is why you need to send a request to determine if you are really connected or not. You can be assured however that if InternetGetConnectedState returns TRUE, that attempting your connection will NOT cause you to be prompted to connect to the default Internet Service Provider.
Be aware that InternetGetConnectedState only reports the status of the default Internet connectoid on Internet Explorer 4.x. If a nondefault connectoid is connected, InternetGetConnectedState always returns FALSE (unless a LAN connection is used). With Internet Explorer 4.x configured to use a LAN connection, InternetGetCo
nectedState always returns TRUE.
Internet Explorer 5 behaves differently. If you are currently dialed into a different dial-up in Internet Explorer 5, InternetGetConnectedState reports dial-up connection status as long as any connectoid is dialed or an active LAN connection exists.


There are some other ways to try to determine if you currently have a connection to a particular network resource. The IsDestinationReachable() function can be used to find out if there is a current connection to an address. However, he IsDestinationReachable() function is only concerned with whether the IP address is reachable from your computer. It does not work through HTTP proxies or firewalls that restrict ICMP ping packets.
It is also possible to use RasEnumConnections to enhance your code so that you can tell if there is an active dialup connection that might have Internet access even though it is not the default Internet dialup connectoid.


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Peter Amick
Baybuild Solutions

[This message has been edited by Peter Amick (edited December 16, 2000).]

[Scott Turchin]

For the purpose of just making sure the guy is online before sending an email the above one should work just fine.
I know he's not on a lan and it's a dialup, now the concern would be maybe he has two dialups but we have information that it's not so that should work pretty good


But I will make a note of the other one as well, that's a nice looking function

Thanks!


Scott


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Scott
mailto:[email protected][email protected]</A>