Question

Is it possible to connect to remote host with indy client and send data to the local server.
i try something like this and i don’t receive anything:

  Server:=TIdUDPServer.Create;
  Server.OnUDPException:=UDPException;
  Server.OnUDPRead:=UDPRead;
  Server.Bindings.Add.Port:=10;
  Server.Active:=true;
  //Server is listening to local IP

  Client:=TIdUDPClient.Create;
  with Client do begin
    Host:= '130.204.159.205'; //My IP
    Port:=10;
    Send('Hello');
  end;

My goal is to create client/server applications that will communicate with UDP over internet

Answer 1

UDP is a connectionless transport. It does not guarantee data deliver like TCP does, especially over a large network like the Internet. If TIdUDPServer is not receiving data, then either the packets are not reaching the machine to begin with, or are being blocked before TIdDUPServer can see them. Use a packet sniffer, such as Wireshark, to verify that the packets are reaching the NIC(s) that TIdUDPServer is listening on. If they are not, then you have a networking issue. If they are, then you have an OS issue.