Checking network status in C#

Question

How do I check that I have an open network connection and can contact a specific ip address in c#? I have seen example in VB.Net but they all use the 'My' structure. Thank you.

Answer 1

Well, you would try to connect to the specific ip, and handle denies and timeouts.

Look at the TcpClient class in the System.Net.Sockets namespace.

Answer 2

First suggestion (IP Connexion)

You can try to connect to the IP using something like:

IPEndPoint ipep =  new IPEndPoint(Ipaddress.Parse("IP TO CHECK"), YOUR_PORT_INTEGER);
Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
server.Connect(ipep);

I suggest you to check code for "Chat" program. These program manipulate a lot of IP connection and will give you a good idea of how to check if an IP is available.

Second suggestion (Ping)

You can try to ping. Here is a good tutorial. You will only need to do :

Ping netMon = new Ping();
PingResponse response = netMon.PingHost(hostname, 4);
if (response != null)
{
    ProcessResponse(response);
}

Answer 3

If you're interested in the HTTP status code, the following works fine:

using System;
using System.Net;

class Program {

    static void Main () {
        HttpWebRequest req = WebRequest.Create(
            "http://www.oberon.ch/") as HttpWebRequest;
        HttpWebResponse rsp;
        try {
            rsp = req.GetResponse() as HttpWebResponse;
        } catch (WebException e) {
            if (e.Response is HttpWebResponse) {
                rsp = e.Response as HttpWebResponse;
            } else {
                rsp = null;
            }
        }
        if (rsp != null) {
            Console.WriteLine(rsp.StatusCode);
        }
    }

}

Regards, tamberg

Answer 4

If you just want to check if the network is up then use:

bool networkUp
    = System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();

To check a specific interface's status (or other info) use:

NetworkInterface[] networkCards
    = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces();

To check the status of a remote computer then you'll have to connect to that computer (see other answers)

Answer 5

If you want to monitor for changes in the status, use the System.Net.NetworkInformation.NetworkChange.NetworkAvailabilityChanged event.

          NetworkChange.NetworkAvailabilityChanged += new NetworkAvailabilityChangedEventHandler(NetworkChange_NetworkAvailabilityChanged);

        _isNetworkOnline = NetworkInterface.GetIsNetworkAvailable();



    void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
    {
        _isNetworkOnline  = e.IsAvailable;
    }