Abstract: IPv6 has many advantages over IPv4, such as almost infinite address space, auto-configuration mechanism, a simplified header structure, built-in IPSec protocol, extension headers, and the convectivc label support and so on. Nowadays, Applications based on network become more and more popular, and people pay more attention to the security of network communication as before. Network products such as IDS have already played a very important role in network.As the IPv6 time is coming, this paper proposed an improved model of IPv6 Intrusion Detection System. , which using a combination of dual stack, IPv4 protocol analysis, and network auditing techniques. We expect this system can be applied in IPv6 environment as well as IPv4 to IPv6 transition environment to play a more efficient role to detect network intrulions.

Key words: Intrusion dctcction, Protocol analysis, Network audit