Now i got another question. I tried using QNetworkConfigurationManager. If connection situation changes program succesfully sends a signal. The signal is onlineStateChanged(bool) If i use QNetworkConfigurationManager::isOnline() function inside a constructor. It fails. Maybe a bug? Here is my code inside constructor : networkConfigurationManager = new QNetworkConfigurationManager(this); // If there is network connection, close the program if(networkConfigurationManager->isOnline() == true) { this->close(); }