3 files changed, 27 insertions, 2 deletions
diff --git a/cpp/src/Ice/Instance.cpp b/cpp/src/Ice/Instance.cpp
index 5f9034be027..66dc8abb135 100644
--- a/cpp/src/Ice/Instance.cpp
+++ b/cpp/src/Ice/Instance.cpp
@@ -1316,8 +1316,9 @@ IceInternal::Instance::Instance(const CommunicatorPtr& communicator, const Initi
         
         _proxyFactory = new ProxyFactory(this);
 
-        bool ipv4 = _initData.properties->getPropertyAsIntWithDefault("Ice.IPv4", 1) > 0;
-        bool ipv6 = _initData.properties->getPropertyAsIntWithDefault("Ice.IPv6", 1) > 0;
+        const bool isIPv6Supported = IceInternal::isIPv6Supported();
+        const bool ipv4 = _initData.properties->getPropertyAsIntWithDefault("Ice.IPv4", 1) > 0;
+        const bool ipv6 = _initData.properties->getPropertyAsIntWithDefault("Ice.IPv6", isIPv6Supported ? 1 : 0) > 0;
         if(!ipv4 && !ipv6)
         {
             throw InitializationException(__FILE__, __LINE__, "Both IPV4 and IPv6 support cannot be disabled.");
diff --git a/cpp/src/Ice/Network.cpp b/cpp/src/Ice/Network.cpp
index cf8a77defbe..ce28c1bac3f 100644
--- a/cpp/src/Ice/Network.cpp
+++ b/cpp/src/Ice/Network.cpp
@@ -1097,6 +1097,29 @@ IceInternal::compareAddress(const Address& addr1, const Address& addr2)
 }
 
 #ifdef ICE_OS_WINRT
+bool
+IceInternal::isIPv6Supported()
+{
+    return true;
+}
+#else
+bool
+IceInternal::isIPv6Supported()
+{
+    SOCKET fd = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
+    if(fd == INVALID_SOCKET)
+    {
+        return false;
+    }
+    else
+    {
+        closeSocketNoThrow(fd);
+        return true;
+    }
+}
+#endif
+
+#ifdef ICE_OS_WINRT
 SOCKET
 IceInternal::createSocket(bool udp, const Address&)
 {
diff --git a/cpp/src/Ice/Network.h b/cpp/src/Ice/Network.h
index 179ebab9582..01418b714cb 100644
--- a/cpp/src/Ice/Network.h
+++ b/cpp/src/Ice/Network.h
@@ -216,6 +216,7 @@ ICE_API ProtocolSupport getProtocolSupport(const Address&);
 ICE_API Address getAddressForServer(const std::string&, int, ProtocolSupport, bool);
 ICE_API int compareAddress(const Address&, const Address&);
 
+ICE_API bool isIPv6Supported();
 ICE_API SOCKET createSocket(bool, const Address&);
 ICE_API SOCKET createServerSocket(bool, const Address&, ProtocolSupport);
 ICE_API void closeSocketNoThrow(SOCKET);