IPv6 provides more address space, improved address design, and greater security than IPv4. Different transition mechanisms can be used to migrate from IPv4 to IPv6 which includes dual stack networks, tunnels and translation technologies. Within all of this, network security is an essential element and therefore requires special attention. This paper analyses two transition technologies which are dual stack and tunnel. Both technologies are implemented using Cisco Packet Tracer and GNS3. This work will also analyse the security issues of IPv6 to outline the most common vulnerabilities and security issues during the transition. Finally, the authors will design and implement the dual stack, automatic and manual tunnelling transition mechanisms using Riverbed Modeler simulation tool to analyse the performance and compare with the native IPv4 and IPv6 networks.