title: C++ Qt application working but gives warning "qt.network.ssl: QSslSocket: cannot resolve SSLv2_server_method"
body: <p>I have written a C++ Qt application (QtCreator version 4.8 based on Qt 5.12.0) running on Linux mint version 18.3 that makes use of QNetworkAccessManager and related classes. It is basically a Betfair HTTPS client application that communicates with the Betfair servers. I have openSSL installed (version 1.0.2g).</p>
  
  <p>Basically my application works perfectly, but I get the <strong>qt.network.ssl: QSslSocket: cannot resolve SSLv2_server_method</strong> (twice) on the application output tab in QtCreator. I am able to successfully login and interact with the API - everything looks and behaves well! I have even used wireshark to inspect the packets which certainly look to be encrypted.</p>
  
  <p>I have seen other answers on here and on the web saying that Ubuntu ships openSSL with disabled openSSLv2 due to instability and recommendations for recompilation WITH openSSLv2 enabled. But as my application is actually working, I am uncertain if this is necessary?</p>
  
  <p>Basically my question is what are the implications of this warning to my software (which appears to be working exactly as intended) in regards to security? I really don't want to ignore a warning without knowing what it is there for. I only know the basics of how SSL works so am a little out of my depth in knowing how to proceed here.</p>
  
  <p><strong>EDIT:</strong> Some answers have led me to discover that the warning is triggered at the point in which a QSslKey is created from my key file. Actual code causing it is:</p>
  
  <pre><code>QByteArray keydata = kfile.readAll();
  QSslKey pkey(keydata,QSsl::Rsa);   // Warning fires after this line executed
  if(pkey.isNull()) {
      qWarning("The key has no content.");
  }
  </code></pre>