Check Network Status

Question

I want to check the network status if network is down, I mean if my network is down then I want to find out by programmatically using C#/VB.net, to find out which router, or server etc is down due to which the network is also down,

Hope I have explain my question, if you want more explanation Please tell me.

I want to check if there is router down in the network connection or some other problem, As there are lot of techniques to check the up or down of the network, but which due to which device on the network the net work down, that is my problem.

Answer 1

You can pinvoke InternetGetConnectedState(). Pass 0 for the flags and if it returns true, there is an active internet connection.

Answer 2

Try PInvoke (see pinvoke.net).

Answer 3

For some of my 3-tier application that use WCF, I use a multistep test to check why I cannot access the online data.

At first, we check if the computer is quarantined (saw this feature at the launch event of Windows 2008)

ManagementScope scope = new ManagementScope(@"\root\nap");
scope.Connect();

ObjectQuery query = new ObjectQuery("SELECT * FROM NAP_Client");
using (ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, query))
{
    int isolationState = 0;
    foreach (ManagementObject m in searcher.Get())
    {
        isolationState = int.Parse(m["systemIsolationState"].ToString());
    }

    if (isolationState == 3) // 3 means in quarantine
    {
        //NAP is preventing the computer access to the network
        ....do something
    }
}

Then we proceed with testing if we have access to the internet using this API:

[DllImport("wininet.dll")]
private extern static bool InternetGetConnectedState(out ConnectedStateFlag lpdwFlags, int dwReserved);

[Flags]
private enum ConnectedStateFlag : int
{
    Configured = 0x40,
    LAN = 0x02,
    RasInstalled = 0x10,
    Modem = 0x01,
    ModemBusy = 0x08,
    Offline = 0x20,
    Proxy = 0x04
}

Then, I open a socket and try connecting to the server address.

Then I try creating an instance of a web service to see if IIS is running properly and is not causing any error.

Then I call a function on the web service that tells me if the database is online.

Answer 4

Why not use the .Net networking classes?

http://msdn.microsoft.com/en-us/library/system.net.networkinformation.aspx