READ DATA FROM SPECIFIC UDP ""PORT""

Marco Flad

I have a device on the network that sends and Receive UDP packets on port = 26000 I can send to it but cant receive from the Device Because i cant specify the receiving port = 26000 on my program.
every time i close - open the program the program sending on different port (Randomly change).
i figured it out by use a packet sender program :

i Send the packet From My PC and Received on "PACKET SENDER"
From My IP And random Port
then i send the packet back from "Packet Sender " to my IP and "This random Port and successfully received it on my program

so there is away to Receive the data on specific port .
CODE :

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);

     socket = new QUdpSocket(this);     
     socket->bind(QHostAddress("192.168.50.55"),26000);  
     connect(socket, SIGNAL(readyRead()), this, SLOT(readyRead()));

}

Widget::~Widget()
{
    delete ui;
    socket->close();
}


void Widget::readyRead()
{

    // when data comes in
     QByteArray buffer;
     buffer.resize(socket->pendingDatagramSize());
     QHostAddress sender;
     quint16 senderPort;

     socket->readDatagram(buffer.data(), buffer.size(),&sender, &senderPort);
     qDebug() << "Message from: " << sender.toString();
     qDebug() << "Message port: " << senderPort;
     qDebug() << "Message: " << buffer;
     qDebug() << sizeof (buffer);

     ui->textEdit->append(buffer.toHex());

}

thanks

Marco Flad

i solved it by using QUDPSocket function derived from QAbstractSocket:

socket->bind(26000, QUdpSocket::ShareAddress);

instead of :

socket->bind(QHostAddress("192.168.50.55"),26000);

Kent-Dorfman

Try your original code with the address of 0.0.0.0

I believe you may need privilege to bind to a specific interface.