On Wed, Jun 13, 2012 at 4:23 AM, Masataka Ohta wrote:
I just need a UPnP capable NAT to restore the end to end transparency.
You're not restoring transparency, you're restoring communication after stateful reconfiguration of the network for each service. It is not transparent when you have to negotiate an inbound path for each service. Even for apps that work today through local NATs, the future is dim. Increasing use of carrier NAT will force apps to additionally try Port Control Protocol to overcome evolving IPv4 brokenness. UPnP is inadequate for carrier NAT due to its model assuming the NAT trusts its clients. When TCP headers are being rewritten, it's a strong hint that transparency has been lost, even if some communication remains possible. Cheers, Dave Hart