Since IPv4 Private Networks are behind NAT (Network Address Translation) devices. So, to Bypass the Binding Update and Binding Acknowledgment by NAT, we need to encapsulate it in UDP (User datagram Protocol) Packets. Hence, the Dual Stack Mobile IPv6 should support NAT Traversal and Detection . This Book provides an overview of network address translation (NAT) and its detection and traversal on dual stack implementation on Mobile IPv6 (DSMIPv6). In DSMIPv6 the MIP6D daemon should bypass NAT, when Mobile Node is behind NAT device in IPv4 Foreign Link. So for proper securing and fully functionality of NAT traversal, it should be IP Security Protected. Book presents design and implementation of NAT traversal capability and keeps alive functionality with IP Security in IKEv2 (Internet Key Exchange version 2) implementation for proper Data Communication. It also implements how IP Security integrate with NAT. With the support of this mechanism the mobile node is able to move freely from IPv4 to IPv6 and vice-versa. The main objective of not breaking connectivity at the time of switching from one network to other is accomplished be this book.