private void start_listener()
{
                ClientListener = new TcpListener(IPAddress.Parse(server_ip), Convert.ToInt32(server_port));
                ClientListener.Start();
                while (true)
                {
                    client_connected(ClientListener.AcceptTcpClient());
                }
}

private void client_connected(TcpClient client)
{
                //обработка
}

        protected TcpListener ClientListener;
        protected TcpClient ClientSocket;
        protected Thread th1;
        public static string server_ip = string.Empty;
        public static string server_port = string.Empty;

        internal void start_potok()
        {
            Protection.Ban.ban_del();
            th1 = new Thread(start_listener);
            th1.Start();
        }

        internal void stop_potok()
        {
            th1.Abort();
            if (ClientSocket != null)
            {
                ClientSocket.Close();
            }
            ClientListener.Stop();
        }

        private void start_listener() //тут только процедура старта и начала ожидания входящих коннектов
        {
            try
            {
                ClientListener = new TcpListener(IPAddress.Parse(server_ip), Convert.ToInt32(server_port));
                ClientListener.Start();
                ClientSocket = default(TcpClient);
                while (true)
                {
                    ClientSocket = ClientListener.AcceptTcpClient();
                    client_connected(ClientSocket);
                }
            catch (ThreadAbortException ex)
            {
                //не ловим это исключение
            }
            catch (Exception ex)
            {
                MessageBox.Show("Ошибка сервера авторизации для клиентов: " + ex.Message);
            }
        }

        private void client_connected(TcpClient client)
        {
            //тут всякие проверки на бан и тому подобное
            LoginClientProc lcp = new LoginClientProc(client);
        }

    class LoginClientProc
    {
        internal EndPoint address;
        internal TcpClient client;
        internal NetworkStream stream;
        private byte[] buffer;

        internal LoginClientProc(TcpClient Client)
        {
            address = Client.Client.RemoteEndPoint;
            client = Client;
            stream = Client.GetStream();

            new System.Threading.Thread(read).Start();
        }

        void read()
        {
            try
            {
                buffer = new byte[2];
                stream.BeginRead(buffer, 0, 2, new AsyncCallback(OnReceiveCallbackStatic), null);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        private void OnReceiveCallbackStatic(IAsyncResult result)
        {
            int rs = 0;
            try
            {
                rs = stream.EndRead(result);

                if (rs > 0)
                {
                    short Length = BitConverter.ToInt16(buffer, 0);
                    buffer = new byte[Length - 2];
                    stream.BeginRead(buffer, 0, Length - 2, new AsyncCallback(OnReceiveCallback), result.AsyncState);
                }
                else
                    //0 = клиент отключился
            }
            catch (Exception s)
            {
            }
        }

        private void OnReceiveCallback(IAsyncResult result)
        {
            stream.EndRead(result);

            byte[] buff = new byte[buffer.Length];
            buffer.CopyTo(buff, 0);
            if (!тут_проверка_на_правильность_пакета)
            {
                //выдаем ошибку
            }
            else
            {
                handle(buff);
                new System.Threading.Thread(read).Start();
            }
        }

        private void handle(byte[] buff)
        {
            byte id = buff[0];
            switch (id)
            {
                //кейсы_под_заголовки_пакетов
                default:
                    //неизвестный_пакет
                    break;
            }
           //овтет_на_пакеты
    }