On Apr 20, 2010, at 12:55 PM, Joe Abley wrote:
On 2010-04-20, at 15:31, Roger Marquis wrote:
If this were really an issue I'd expect my nieces and nephews, all of whom are big game players, would have mentioned it. They haven't though, despite being behind cheap NATing CPE from D-Link and Netgear.
I have heard it said before that there is significant cooperation and/or software engineering work between some or all of those who make residential gateways and those who make multi-player games to achieve this end result. The opinion I heard vocalised at the time was that it would have been a lot easier to reach this state of affairs if there had been standardisation of NAT in v4 at an early stage. As it is, peer-to-peer apps like games require significant if-then-else to make anything work.
The fact that they work is usually due to uPNP or another inbound NAT-T solution. All of these will be very unlikely to work in an LSN environment. None of them work in a multilayer NAT environment.
Address conservation aside, the main selling point of NAT is its filtering of inbound session requests.
If that was all that was required, you could sell a stateful firewall that didn't do NAT, and everybody would buy that instead because it would make things like iChat AV break less. Apparently there are other reasons to buy and sell devices that NAT (e.g. my ISP gives me one address, but the laptop and the Wii both want to use the internet).
In IPv4, yes, there are other reasons. (Address conservation). In IPv6, it shouldn't be a problem to sell a stateful firewall that doesn't do NAT. Owen