So the application is broke with IPv4 and NAT, it is broke with IPv6 as it currently is, and somehow in the future it will be able to be re-written in IPv6 and made to work?
Most of the problems that I encounter with NAT and applications deal with protocols that have a control channel and then spawn separate streams frequently which are UDP. H323 is a perfect example. Both ends and the intermediate NAT devices have to understand how to handle the sub-channels.
This problem won't go away with IPv6 as firewalls will still need to understand the sub-flows. Additionally, we will be living in an IPv4 AND IPv6 world with NAT so not only will you likely have to go through an IPv4 NAT you also probably will have to go through a protocol tunneling device for some large set of users.
Most of the problems that I encounter with NAT and applications deal with protocols that have a control channel and then spawn separate streams frequently which are UDP. H323 is a perfect example. Both ends and the intermediate NAT devices have to understand how to handle the sub-channels.
This problem won't go away with IPv6 as firewalls will still need to understand the sub-flows. Additionally, we will be living in an IPv4 AND IPv6 world with NAT so not only will you likely have to go through an IPv4 NAT you also probably will have to go through a protocol tunneling device for some large set of users.