Send UDP packet to a public IP using Boost.asio - c++

Question

I want to send UDP packets to my static IP 122.***.***.*** where an UDP server listens on port 1213.
udp::resolver resolver(io_serviceSend);
udp::resolver::query query(udp::v4(),"122.***.***.***","1213");
udp::endpoint receiver_endpoint = *resolver.resolve(query);
udp::socket socket(io_serviceSend);
socket.open(udp::v4());
boost::shared_ptr<std::string> message(new std::string("Transfer"));
socket.send_to(boost::asio::buffer(*message), receiver_endpoint);
but this fails. Is it because i am sending it to the private port rather than sending it to the NAT's port. but for TCP it works perfectly.
Can some one explain me the theory or post a good link.
and my server code is
UDPTunnel::UDPTunnel(boost::asio::io_service& io_service)
:socket_(io_service, udp::endpoint(udp::v4(), 1213))
{
start_receive();
}
void UDPTunnel::start_receive()
{
socket_.async_receive_from(
boost::asio::buffer(recv_buffer_), remote_endpoint_,
boost::bind(&UDPTunnel::handle_receive, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
cout << "\nUDP Started To Listening";
}
void UDPTunnel::handle_receive(const boost::system::error_code& error,std::size_t)
{
cout << "\nUDP Recieved Message";
if (!error || error == boost::asio::error::message_size)
{
cout << "\nRecieved Message";
}
}