Application translation for IPv6 at NAT-PT

The next generation Internet protocol, IPv6 which uses 128 bits Internet addresses will replace the current IPv4 protocol gradually from 2005. After 2010 IPv6 will be the main ocean of Internet or network. But until completely transition to IPv6, IPv4 and IPv6 will coexist and network devices must support IPv4 and IPv6 at the same time. Especially general users want to use Internet and applications without big changes even if networks are changed to IPv6. This paper describes ALG (application layer gateway) for IPv6 which translates application layer data in NAT-PT transition mechanism. With the design and implementation of DNS-ALG and FTP-ALG, we research the application layer gateway and examine the relationship between IP layer translation and application layer translation. As IPv6 is more deployed, not only IP layer translation, but also application layer translation has more necessity.