Checking network status in C#

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

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

NetworkChange.NetworkAvailabilityChanged += new NetworkAvailabilityChangedEventHandler(NetworkChange_NetworkAvailabilityChanged);

        _isNetworkOnline = NetworkInterface.GetIsNetworkAvailable();



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

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);

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

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);
        }
    }

}