IPv4 is the current version of Internet Protocol. This is used to communicate the data over the Internet and makes interaction between different applications as possible. Network layer protocol was developed with the objective that it should ease the communication between nodes in the Internet. Address space of IPv4 is just 32 bits. Due to the very fast growth of Internet in the last two decades IPv4 address space is depleted. In order to overcome this problem and other disadvantages of IPv4, a new Internet protocol called IPv6 was developed. IPv6 has 128 bits address, auto configuration capability and IPSec is inbuilt. Due to these advantages now everyone in the Internet is migrating from IPv4 to IPv6. In spite of these advantages that IPv6 possesses, it also has some security issues. Various attacks that are prevailing in today’s Internet such as virus, worms and DDoS attacks are also there in IPv6 networks also. Among these attacks DDoS attacks pose a major threat to the Internet society. IPv6 has some security issues related with its Neighbor Discovery protocol, Routing Options extensions header and ICMPv6 protocol. Attackers can exploit these security holes of IPv6 to launch a DDoS attack in an IPv6 network. A distributed denial of service (DDoS) attack is a large-scale, coordinated attack on the availability of services of a victim system or network resources, launched indirectly through many compromised computers on the Internet. The fig: 1 explains the number of