C# server socket doesn't connect to C++ client socket

Hi,

I have am trying to integrate our C# interface with a vendor's C++ message simulator, but I'm having trouble getting the C# server to recognize a client connect from the C++ app.  I pulled example C# code to setup the server and I've inherited C++ client code from my vendor, so I'm not sure if the different languages are the problem or if I'm mixing async and sync sockets or what.  When I try to set a breakpoint at the client connect callback in the C# server, it is never triggered, so it is never seeing a connection.    

I'm posting the code below, but here's what I know at this point:
- the firewall is off.  
- the C# socket code has a separate C# client snippet that connects and trades messages correctly, so I know that whatever the difference is in my code, it is due to differences in the way the C++ client is implemented, because the C# server works with it's C# client.  
- same thing happens with the C++ server/client, so again, I know the problem is in the difference in implementations, because the C++ client/server work together.    
- the C++ client code never fails at the connect call - even if I don't have a server running, the client program returns a good connect call and proceeds to send 216 bytes of data after that.  
- I don't have the liberty of changing the C++ client code.  I have to make the C# server code adapt to fit the C++ client code.  
- when I run netstat while running the client and server, I never see a connection.  

So to reiterate, my end goal is to adapt the C# server code to make it work with the C++ code as is.  My code is attached.  My server code appears first (System.Net.Socket), followed by my client code (winsock).   Thanks in advance for your help.  

public void StartListen(int port)
      {
         System.Net.IPAddress ipAdd = System.Net.IPAddress.Parse("127.0.0.1");
         IPEndPoint ipLocal = new IPEndPoint(ipAdd, port);
         Console.WriteLine("Local address and port : {0}",ipLocal.ToString());
         m_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

         //bind to local IP Address...
         //if ip address is allready being used write to log log
         try
         {
            m_socket.Bind(ipLocal);
         }
         catch (Exception ex)
         {
            Debug.Fail(ex.ToString(), string.Format("Can't connect to port {0}!", port));
            return;
         }
         //start listening...
         m_socket.Listen(4);
         // create the call back for any client connections...
         m_socket.BeginAccept(new AsyncCallback(OnClientConnection), null);

      }

      private void OnClientConnection(IAsyncResult asyn)
      {
         if (m_Closed)
         {
            Console.WriteLine("Socket closed");
            return;
         }

         try
         {
            m_socWorker = m_socket.EndAccept(asyn);

            RaiseClientConnected(m_socWorker);

            m_listener = new SocketListener();
            m_listener.MessageReceived += OnMessageReceived;
            m_listener.Disconnected += OnClientDisconnection;

            m_listener.StartReceiving(m_socWorker);
         }
         catch (ObjectDisposedException odex)
         {
            Debug.Fail(odex.ToString(), "OnClientConnection: Socket has been closed");
         }
         catch (Exception sex)
         {
            Debug.Fail(sex.ToString(), "OnClientConnection: Socket failed");
         }

      }

      private void OnClientDisconnection(Socket socket)
      {
         RaiseClientDisconnected(socket);

         // Try to re-establish connection
         //m_socket.BeginAccept(new AsyncCallback(OnClientConnection), null);
         m_socket.Accept();
         if (m_socket.Connected)
            Console.WriteLine("Connected");
      }

      public void SendMessage(string mes)
      {
         if (m_socWorker == null)
         {
            return;
         }

         try
         {
            Object objData = mes;
            byte[] byData = System.Text.Encoding.ASCII.GetBytes(objData.ToString());
            m_socWorker.Send(byData);
         }
         catch (SocketException se)
         {
            Debug.Fail(se.ToString(), string.Format("Message '{0}' could not be sent", mes));
         }

      }

      public void Close()
      {
         try
         {
            if (m_socket != null)
            {
               m_Closed = true;

               if (m_listener != null)
               {
                  m_listener.StopListening();
               }

               m_socket.Close();

               m_listener = null;
               m_socWorker = null;
               m_socket = null;
            }
         }
         catch (ObjectDisposedException odex)
         {
            Debug.Fail(odex.ToString(), "Stop failed");
         }
      }

      private void OnMessageReceived(string message)
      {
         if (MessageReceived != null)
         {
            MessageReceived(message);
         }
      }

      private void RaiseClientConnected(Socket socket)
      {
         if (ClientConnect != null)
         {
            ClientConnect(socket);
         }
      }
}

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bool SendMsg(char* host, int port, char* msg, size_t msgLength)
{
#ifdef WIN32
  // Start Winsock.
  WSAData wsaData;
  WSAStartup(MAKEWORD(1, 1), &wsaData);
#endif

  // Create socket.
  SOCKET theSocket = socket(AF_INET, SOCK_DGRAM, 0);
  if (theSocket != INVALID_SOCKET) 
  {
    // Connect.
    unsigned long address = inet_addr(host);
    if (address != INADDR_NONE) // broadcast address is illegal
    {
      sockaddr_in destination;
      destination.sin_family = AF_INET;
      destination.sin_addr.s_addr = address;
      destination.sin_port = htons((u_short)port);
      memset(&(destination.sin_zero), '\0', 8);

      connect(theSocket,(LPSOCKADDR)(&destination),sizeof(destination));

      // Send message.
      int bytesSent;
      bytesSent = sendto(theSocket, msg, (int)msgLength, 0, 
        (sockaddr*)&destination, sizeof(sockaddr_in));

      // Shutdown socket.
      shutdown(theSocket, 0x01);
    }
    else
    {
      cerr << "The destination IP address is not valid. Note: The IP address 255.255.255.255 cannot be used." << endl;
      return true;
    }
  }
  else
  {
    cerr << "Error creating socket." << endl;
    return true;
  }

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