qt-bugs@ issue : N213060
Trolltech task ID : 213187
bugs.kde.org number : 154774, 162600
applied: yes
author: Thiago Macieira <thiago.macieira@trolltech.com>

    the AI_ADDRCONFIG flag was introduced in recent
    specifications of the getaddrinfo(3) function. It tells the resolver
    to look up only address families which are already set up on the
    machine. That is: look up IPv4 if there are IPv4 addresses, look up
    IPv6 if there are IPv6 addresses in any of the network interfaces.

diff --git src/network/kernel/qhostinfo_unix.cpp src/network/kernel/qhostinfo_unix.cpp
index c9d8cb9..d4db2bd 100644
--- src/network/kernel/qhostinfo_unix.cpp
+++ src/network/kernel/qhostinfo_unix.cpp
@@ -137,8 +137,19 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     struct addrinfo hints;
     memset(&hints, 0, sizeof(hints));
     hints.ai_family = PF_UNSPEC;
+# ifdef AI_ADDRCONFIG
+    hints.ai_flags = AI_ADDRCONFIG;
+# endif

     int result = getaddrinfo(hostName.toLatin1().constData(), 0, &hints, &res);
+# ifdef AI_ADDRCONFIG
+    if (result == EAI_BADFLAGS) {
+        // if the lookup failed with AI_ADDRCONFIG set, try again without it
+        hints.ai_flags = 0;
+        result = getaddrinfo(hostName.toLatin1().constData(), 0, &hints, &res);
+    }
+# endif
+
     if (result == 0) {
         addrinfo *node = res;
         QList<QHostAddress> addresses;