3 ms·

The IPv4 traffic gets 'tunneled' between the v4 app and the v4 router over v6.

ninkendo 3y ago
NAT64 is just stateful NAT, exactly the same as IPv4 stateful NAT. It happens to be translating between v4 and v6 as part of the translation, but it’s no different whatsoever from pure-IPv4 NAT in this regard. You can call it “tunneling” if that helps you conceptualize it, sure, but you shouldn’t extend the tunneling analogy to make it seem like it’s conceptually different from IPv4 NAT, because it isn’t. This phrase: > The tunnel that the NAT64 system sets up is time-bound. So while outgoing traffic re-establishes the route, incoming traffic is not stateless. It stops. Makes it seem like NAT64 is doing something conceptually different from what we’ve had for decades with every IPv4 network. It’s not. And when OP says: > When you have an IPv4 <> IPv4 UDP tunnel you can just send traffic. If one device is behind NAT you set up port forwarding. It'll work today, it'll work tomorrow, and in 2 years Everything they just said applies to NAT64 too. You can “set up port forwarding” of your public IPv4 address to forward to an internal IPv6 address too. It’s just NAT! Edit: I think what’s happening in this discussion, is that WirelessGigabit responded to my comment about my home setup, with drawbacks about their T-Mobile setup, which was a bit of a change of subject. It took a few re-readings of their comment for this to become clear. In my toplevel post I’m referring to a scenario where my ISP gives me an IPv4 address, but I don’t have IPv4 enabled in my LAN. (No IPv4 DHCP addresses are being handed out, my router does not have a v4 address on its LAN link.) WirelessGigabit is referring to a setup like in T-Mobile, where they’re putting the NAT64 box somewhere in T-Mobile’s infrastructure, and thus WirelessGigabit has no control over doing things like setting up port forwarding rules, etc. Basically they’re complaining about things I never mentioned about my setup. And as others have pointed out, T-Mobile’s XLAT setup is basically CGNAT by another name, but one where if your use case is pure IPv6, there’s a path to avoiding the NAT issues. This is very different from my case.

NAT64 is just stateful NAT, exactly the same as IPv4 stateful NAT. It happens to be translating between v4 and v6 as part of the translation, but it’s no different whatsoever from pure-IPv4 NAT in this regard. You can call it “tunneling” if that helps you conceptualize it, sure, but you shouldn’t extend the tunneling analogy to make it seem like it’s conceptually different from IPv4 NAT, because it isn’t. This phrase: > The tunnel that the NAT64 system sets up is time-bound. So while outgoing traffic re-establishes the route, incoming traffic is not stateless. It stops. Makes it seem like NAT64 is doing something conceptually different from what we’ve had for decades with every IPv4 network. It’s not. And when OP says: > When you have an IPv4 <> IPv4 UDP tunnel you can just send traffic. If one device is behind NAT you set up port forwarding. It'll work today, it'll work tomorrow, and in 2 years Everything they just said applies to NAT64 too. You can “set up port forwarding” of your public IPv4 address to forward to an internal IPv6 address too. It’s just NAT! Edit: I think what’s happening in this discussion, is that WirelessGigabit responded to my comment about my home setup, with drawbacks about their T-Mobile setup, which was a bit of a change of subject. It took a few re-readings of their comment for this to become clear. In my toplevel post I’m referring to a scenario where my ISP gives me an IPv4 address, but I don’t have IPv4 enabled in my LAN. (No IPv4 DHCP addresses are being handed out, my router does not have a v4 address on its LAN link.) WirelessGigabit is referring to a setup like in T-Mobile, where they’re putting the NAT64 box somewhere in T-Mobile’s infrastructure, and thus WirelessGigabit has no control over doing things like setting up port forwarding rules, etc. Basically they’re complaining about things I never mentioned about my setup. And as others have pointed out, T-Mobile’s XLAT setup is basically CGNAT by another name, but one where if your use case is pure IPv6, there’s a path to avoiding the NAT issues. This is very different from my case.