Delphi | Udp

procedure SendUDPBytes(const AHost: string; APort: Integer; const Bytes: TBytes); var UDPClient: TIdUDPClient; begin UDPClient := TIdUDPClient.Create(nil); try UDPClient.Host := AHost; UDPClient.Port := APort; UDPClient.Send(TIdBytes(Bytes)); finally UDPClient.Free; end; end; The server component operates asynchronously using the OnUDPRead event.

// Process the message (e.g., display in a memo) TThread.Queue(nil, procedure begin Memo1.Lines.Add(Format('[%s:%d] %s', [RemoteIP, RemotePort, ReceivedString])); end); end; delphi udp

procedure TUDPReceiver.OnDataAvailable(const AData: TBytes; AEndpoint: TEndpoint); var Msg: string; begin Msg := TEncoding.UTF8.GetString(AData); // Handle message (use TThread.Queue if updating UI) end; 1. Message Size UDP has a maximum theoretical payload of 65,507 bytes (due to IP and UDP headers). In practice, keep messages under 1,476 bytes to avoid IP fragmentation, which can cause packet loss. 2. Connectionless Nature Do not rely on a “connection” state. Always handle the possibility of no receiver, and implement application-level acknowledgments if needed. 3. Broadcast and Multicast To send a broadcast (all devices on local subnet): In practice, keep messages under 1,476 bytes to

To send raw bytes: