--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-FBB9ED48-3C0F-4B2D-90FC-52127698F253.dita	Thu Jan 21 18:18:20 2010 +0000
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-FBB9ED48-3C0F-4B2D-90FC-52127698F253" xml:lang="en"><title>IPv4/IPv6
+dual-stack</title><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>The IP protocol is responsible for routing the data between networks
+and it employs an addressing system to achieve this. The Internet protocol
+version 4 (IPv4) has a number of security problems and lacks privacy and authentication
+mechanisms below the application layer. IPv6 provided numerous security enhancements,
+such as mandatory implementation of Authentication Header and Encapsulated
+Security Payload.</p>
+<p><i>IPv4/IPv6 dual-stack</i> enables applications to choose the protocol
+to use or automatically select it according to address type. This feature
+is supported from Symbian OS v7.0s onwards.</p>
+<fig id="GUID-E46DA5BE-AB7E-40C6-9A75-1BB7E9D21034"><title>IPv4/IPv6 dual-protocol stack</title><image href="GUID-D81EAF75-EF8C-4B62-8866-439E29325E8A_d0e7676_href.png"/></fig>
+<p>It is possible to establish a secure connection from application to
+application and also from router to router. Security features implemented
+in low-level protocols (like IPv6) are automatically available to higher-level
+protocols and applications.</p>
+<p>For more information, see <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/Networking-subsystem-guide/index.html" format="application/java-archive">Networking</xref>.</p>
+</conbody></concept>
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