Why are my sockets closing after a certain of time?

I would like to know why the sockets i'm opening are closing after a few seconds/minutes.

On the server side i have a UI which shows me the amount of opened connections. So whenever i run the code mentioned below, the amount starts to increase. So when i reach for example 5000 open connections suddenly a X amount of connections drop. No idea why this is happening.

I'm running the method on different threads to speed up the process.

Which problems do i have?

• The sockets are closing automatically after a few seconds/minutes depending on the amount of threads.

• Sometimes it is throwing a SocketException, this happens if i increase the amount of threads.

  System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not respond correctly after a certain time, or the connection made failed because the connected host did not respond

  static void Main(string[] args)
  {
      for (int i = 0; i < 100; i++)
      {
          Thread thread = new Thread(HitOne);
          thread.Start();
      }
  }
  
  static void HitOne()
  {
      while(true)
      {
  
          /*
           * Sleep to prevent network from losing connection
           * (Not sure if this is correct)
           */
          Thread.Sleep(5000);
  
          try
          {
              TcpClient client = new TcpClient(IP, PORT);
          }
          catch (SocketException e)
          {
              Console.WriteLine(e);
          }
      };
  }
  

Is it normal that a socket closes after a certain time? At the beginning i was thinking that a huge amount of threads and connections could drop my network (like a ddos attack would do). I thought maybe the sleep method would solve this issue but it isn't.

• I can't add my server here. The code it way too complex. But i can say that i don't have functionality to closes incoming connections. So normally everything should stay up.

• If you think there is a better way to do this, please let me know.

Thanks in advance.