program do monitorowania sieci, a w zasadzie ISP

using System;
using System.Text;
using System.Collections;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using System.Net.NetworkInformation;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace upcping
{
    class Program
    {
        private static List<DateTime> peaks;

        public enum CtrlTypes
        {
            CTRL_C_EVENT = 0,
            CTRL_BREAK_EVENT,
            CTRL_CLOSE_EVENT,
            CTRL_LOGOFF_EVENT = 5,
            CTRL_SHUTDOWN_EVENT
        }

        public delegate bool HandlerRoutine(CtrlTypes CtrlType);
        
        [DllImport("Kernel32")]
        public static extern bool SetConsoleCtrlHandler(HandlerRoutine Handler, bool Add);

        private static bool ConsoleCtrlCheck(CtrlTypes ctrlType)
        {
            if (peaks.Count > 0)
            {
                Trace.WriteLine("\r\n\r\nPeaks:");

                foreach (var peak in peaks)
                    Trace.WriteLine(peak.ToLongTimeString());
            }

            return false;
        }

        static void Main(string[] args)
        {
            string[] ips = { "192.168.1.1", // router
                             "192.168.100.1", // modem
                             "84.10.148.1", // router UPC #1
                             "89.75.2.161", // router UPC #2
                             "213.180.146.27" }; // onet.pl

            const int interval = 1000; // w ms
            const int packetSize = 32; // w bajtach
            const int timeout = 2000; // w ms
            const int threshold = 100; // w ms

            SetConsoleCtrlHandler(new HandlerRoutine(ConsoleCtrlCheck), true);

            Ping ping = new Ping();
            var tasks = new Task<PingReply>[ips.Length];
            byte[] buffer = Encoding.ASCII.GetBytes(new string('F', packetSize));
            int row = 0;
            peaks = new List<DateTime>();

            TextWriterTraceListener textFileTracer = new TextWriterTraceListener(DateTime.Now.ToShortDateString() + " " +
                DateTime.Now.ToShortTimeString().Replace(':', '.') + ".txt");
            ConsoleTraceListener consoleTracer = new ConsoleTraceListener();
            Trace.Listeners.Add(textFileTracer);
            Trace.Listeners.Add(consoleTracer);
            Trace.AutoFlush = true;

            while (true)
            {
                if (row % 30 == 0)
                {
                    Trace.Write(new string(' ', DateTime.Now.ToLongTimeString().Length));
                    foreach (var ip in ips)
                        Trace.Write(string.Format("{0,16}", ip));
                    Trace.WriteLine("");
                    row = 0;
                }
                row++;

                for (int i = 0; i < ips.Length; i++)
                    tasks[i] = new Task<PingReply>((object ip) => ping.Send(ip.ToString(), timeout, buffer,
                        new PingOptions() { DontFragment = true }), ips[i]);

                var start = DateTime.Now;

                foreach (var task in tasks)
                    task.Start();

                try
                {
                    Task.WaitAll(tasks);
                }
                catch (Exception)
                {
                    Trace.WriteLine("Error");
                    continue;
                }
                finally
                {
                    var elapsed = interval - (int)(DateTime.Now - start).TotalMilliseconds;

                    if (elapsed > 0)
                        Thread.Sleep(elapsed);
                }

                StringBuilder sb = new StringBuilder();
                foreach (var task in tasks)
                {
                    PingReply result = task.Result;

                    if (result.Status == IPStatus.TimedOut)
                        sb.AppendFormat("{0,16}", "timeout");
                    else if (result.Status != IPStatus.Success)
                        sb.AppendFormat("{0,16}", "*");
                    else if (result.RoundtripTime >= threshold)
                    {
                        sb.AppendFormat("{0,16}", "**** " + result.RoundtripTime + "ms");

                        DateTime lastPeak = peaks.FindLast(dateTime => (DateTime.Now - dateTime).TotalSeconds > 30);
                        if (lastPeak == default(DateTime)) peaks.Add(DateTime.Now);
                    }
                    else
                        sb.AppendFormat("{0,14}ms", (result.RoundtripTime == 0) ? "<1" : result.RoundtripTime.ToString());
                }

                for (int i = 0; i < tasks.Length; i++)
                    tasks[i].Dispose();

                string log = sb.ToString();
                
                Trace.WriteLine(DateTime.Now.ToLongTimeString() + log);
            }
        }
    }
}

echo off
:start
echo %date% %time% >> "D:\log\pinglog.txt"
ping wp.pl >> "D:\log\pinglog.txt"
goto start