North American Network Operators Group|
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Re: Access to the IPv4 net for IPv6-only systems, was: Re: WG Action: Conclusion of IP Version 6 (ipv6)
> What has happened? Well, application protocols have evolved to > accommodate NAT weirdness (e.g., SIP NAT discovery), and NATs have > undergone incremental improvements, and almost no end-users care about > NATs. As long as they can use the Google, BitTorrent and Skype, most > moms and dads neither know nor care about any technical impediments > NATs erect between them and their enjoyment of the Internet. Except every service that used to work using direct TCP connections has either moved to UDP, or moved towards having unNATted boxes that people can relay through. While NAT traversal for TCP is theoretically possible, it relies on rarely used features of TCP (Simultaneous open) and good timing, both of which are likely to cause issues. I've never heard of a successful real world application successfully doing this. (Feel free to educate me if you know of a realworld application in common use that does do TCP NAT traversal and has it work a significant amount of the time). Even p2p apps like bittorrent rely on the fact that there are /some/ people /somewhere/ in the swarm that have either configured their NAT to allow pinholing or don't have any NAT between them and the Internet. Plastered everywhere over anything P2P filetransfer related is "poor performance? Add a pinhole to your NAT box!" suggesting quite strongly that NAT is causing large problems for P2P swarms. NAT is hurting applications today, and applications aren't getting deployed (or even written) because of problems NAT causes.