using System;
using System.Collections.Generic;
using System.Text;
using System.Net.NetworkInformation;
namespace test
{
  class Program
  {
    static void Main(string[] args)
    {
      GetTcpConnections();
    }
    public static void GetTcpConnections()
    {
      IPGlobalProperties properties = IPGlobalProperties.GetIPGlobalProperties();
      TcpConnectionInformation[] connections = properties.GetActiveTcpConnections();
      foreach (TcpConnectionInformation t in connections)
      {
        Console.Write("Local endpoint: {0} ", t.LocalEndPoint.ToString());
        Console.Write("Remote endpoint: {0} ", t.RemoteEndPoint.ToString());
        Console.WriteLine("{0}", t.State);
      }
      Console.WriteLine();
      Console.ReadLine();
    }
  }
}

Local endpoint: 127.0.0.1:1025 Remote endpoint: 127.0.0.1:1026 Established
Local endpoint: 127.0.0.1:1026 Remote endpoint: 127.0.0.1:1025 Established
Local endpoint: 127.0.0.1:1028 Remote endpoint: 127.0.0.1:16992 CloseWait
Local endpoint: 127.0.0.1:1110 Remote endpoint: 127.0.0.1:4900 Established
Local endpoint: 127.0.0.1:2754 Remote endpoint: 127.0.0.1:1110 CloseWait
Local endpoint: 127.0.0.1:2762 Remote endpoint: 127.0.0.1:1110 CloseWait
Local endpoint: 127.0.0.1:2773 Remote endpoint: 127.0.0.1:1110 CloseWait
Local endpoint: 127.0.0.1:2913 Remote endpoint: 127.0.0.1:1110 CloseWait
Local endpoint: 127.0.0.1:3014 Remote endpoint: 127.0.0.1:1110 CloseWait
Local endpoint: 127.0.0.1:3531 Remote endpoint: 127.0.0.1:1110 CloseWait
Local endpoint: 127.0.0.1:4012 Remote endpoint: 127.0.0.1:1110 CloseWait
Local endpoint: 127.0.0.1:4900 Remote endpoint: 127.0.0.1:1110 Established