Teredo Tunnel Connection, this should be a Fast Reverse Proxy, Microsoft u must know, Frp...

First and First, IPV4 have Public address and Private address bcz NAT technology, more NAT means ur network have to pass more gateway (basically network have to pass more hardware), and Public IPV4 are already spend out since 2019, that's why we need IPV6 works!

Teredo is a Tunnel, and im pretty sure it's not a new technology, it's a service call Fast Reverse Proxy right? so bcz NAT technology we can't directly connect other people, but IPV6 can actually don't need NAT bcz IPV6 have many Public address pools (even u can use NAT with IPV6 but why), IPV4 can't do that, that's why Teredo Tunnel are here, right?

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So, more people use Teredo Tunnel service, more Teredo server costs, and that's why this should not be always a free service: Teredo for testing NAT Type? sure it's fine, but use for online game? i sug don't, we are encountering many teredo issue when using IPV6 with No NAT, always Network Unmanaged, and i can't join online session when playing Forza Horizon 4 with IPV6, but when i disable IPV6 i can play Forza Horizon 4 online game just like normal, and also my network is very fine and i can play Forza Horizon 5 online game with IPV4/IPV6, and Forza Horizon 5 doesn't use Teredo (at all time i guess).

i sug, if Teredo use for testing NAT Type, it can be a free service, but if use for other such like online game, it depends on the following scenarios:

A. if the server must able to contain many users and most time people are using P2P connection, Teredo will try to identify NAT Type, if the network can able to directly connect public network, Teredo won't work, otherwise Teredo will start Frp, Frp won't be a free service. for free user this service will provide a limited network data usage and limited usage time daily; if personal network data usage is running dry, user will get notice and will get network function limit to prevent all personal network data usage spend out; but after all personal network data usage or usage time spend out, user network will disconnect from Teredo;

B. if the server only just matchmaking users, create P2P connection and recording data, Teredo won't work bcz that's the server must care about;

C. if only just for P2P connection, Teredo can enable by using command, but same as Situation A.

For Forza Horizon 4? sug follow Situation A, after disconnect from Teredo, online function will be disable until user purchased Xbox Game Pass Core or get daily limited network data usage and limited usage time, i know that need a game update to do that, but im not always need Teredo, it supposed to be not always enable in this game.

:)