QUdpSocket can't receive data from specific interface

Ivan Perynets

Hi all,
I am trying to receive data from a hardware device using a UDPSocket.
I have successfully connected to port via UDPSocket->bind

 if( socket->bind(QHostAddress("192.168.250.151"), port )

but the data not coming.

When I opened WireShark and select the Ethernet adapter the data receive successfully.

Another words UDP data from device receiving only when WireShark is open.

Mayby I need to specify Ethernet adapter to the port...
Any ideas? Thanks.

![alt text]( image url)

Christian Ehrlicher

Ist the port correct, does your host really have the ip address 192.168.250.151? Do you have correctly configured the firewall (esp. on windows this is a common problem).

Ivan Perynets

Firewall and antivirus is turned off.
I wrote local IP address and the port manually, but nothing changed.

if( socket->bind(QHostAddress("192.168.250.151"), 52100 ) )    
    {
        qDebug() << "PASS, Port Num : is connected";
    }
    else
    {
        qDebug() << "FAIL connected to UDP";
}

It is really strange behavior.

Christian Ehrlicher

I'm pretty sure it's the windows firewall. Try to send to a dedicated adress instead broadcast to see if it helps but QUdpSocket can handle both correctly. See also the examples and try them out: https://doc.qt.io/qt-6/qudpsocket.html#details