I'd love to use it, but honestly it's fairly complex to even understand if I can use it. From my home ISP to my compute provider(s), I've not even done enough research to know if I can use it.
Last I recall (years ago) my buddy was running some type of VPN through Comcast just to be able to use IPv6 properly. That's when I decided it was still too new for me.
Clearly I don't know anything on the subject, and I'm not claiming to. These are one of the areas where I don't know, don't desire to know, and want it to "just work". I am however interested in making my applications compliant asap, but until I can reliably use it, I've not even attempted.
So with that big pile of ignorance, are we "there yet"? Ie, could I build applications and run them on a IPv6 compatible host, with hit it with my home ISP with a reasonable expectation that everything will work? (assuming my code works, of course).
I feel like I need a "caniuseIPv6.com" site, similar to https://caniuse.com. From the outside, IPv6 implementation and support seems bizarrely cryptic.
I'm a current Comcast customer. I own my own (non-Comcast-purchased) router (an RT-AC68U) and cable modem (a Motorola Surfboard).
On the modem side, nothing needed to be done for IPv6. Any firmware updates or configuration needed is done by Comcast.
On the router side, there is a dedicated IPv6 configuration page. Settings are:
• Connection Type: Native
• All other available settings: Set to either 'Enable' or 'Stateless'.
That was it. My Mac has IPv6 configuration set to configure 'Automatically', and I get an IP. If I go to plain Google and ask it "what's my ip" I get a IPv6 IP back.
On my iPhone, on wifi, if I do the same "what's my ip" Google search, I get an IPv6 back. My carrier is Ting GSM; if I turn off wifi and do the same Google search, I get a different IPv6 IP back.
At work, IPv6 is rolling out _very_ slowly, but I was able to get a fixed IPv6 address. That has been programmed into the configuration for my laptop's USB-Ethernet adapter, so I have IPv6 at my desk at work. Although most work services are not IPv6-enabled, DNS is.
And at home, IPv6 is enabled and is in active use, both on desktop and on mobile.
If I'm at home and my computer has an IPv6 address, and I want to visit a site that has only IPv4 address, where does the NAT happen? Or does it happen? Or is it sort of like ASCII in UTF-8; all IPv4 addresses are directly representable in the IPv6 format? But even if that, how does the IPv4 service send a response back to me?
At home you will be "dual stack". That means your operating system implements an entire IPv4 network stack and an entire IPv6 stack, it will see this site only has IPv4, and use IPv4. If your IPv4 access goes through a NAT, then it will use the NAT exactly as if you didn't have IPv6 at all.
(Yes, all IPv4 addresses can be represented as IPv6 addresses in a reserved zero prefix network, some network APIs just offer IPv6 and then treat IPv4 addresses this way for convenience, but we obviously don't route packets this way since those would be IPv6 packets, yet they're for an IPv4 destination which can't read them)
In some very large deployments they do v6-only. Everything internally is IPv6, when you connect to that IPv4 only site you'd actually connect to a company-provided gateway that speaks IPv6 on your side but IPv4 to the outside world.
If you're big enough this makes loads of sense - now you have this vast address space for everything, all your systems are simply configured for IPv6 only (not twice the configuration) and it pretty much just works. You buy some specialist appliances at the edge for that translation, but your users only have IPv6 stuff.
Wouldn't it have been nice for IPv6 to provide a basic translation protocol or mapping for seamless migration and backwards compatibility? Where your IPv4 address is also an IPv6 address?
I'd welcome someone showing me how that was basically impossible, but I don't see why the entire IPv4 space isn't in a special prefix / address space of ipv6 since they allegedly have so many atoms of mappings.
This was done, it was called 6to4 and it worked pretty well when native IPv6 was less available. The gateways had an anycast IPv6 address too so you didn't have to manually configure the address of your gateway to the real IPv6 internet.
As an example, if we look at https://github.com/GoogleCloudPlatform/container-vm-guestboo... then there are a couple of things here that are IPv4 only. The first is that the application is only configured to listen on the IPv4 address family, app.run(host='0.0.0.0', port=80), on linux if that was changed to app.run(host='::', port=80) this the application would be able to receive both IPv4 and IPv6 requests (on windows the situation is different however)
The second, and less important change, is that the redis connection is using 127.0.0.1, and if instead it was using "localhost" then that would resolve to the correct address family. This is less important as it is only relevant if there is no IPv4 on the server host, the first change would allow your app to accept IPv6 traffic.
Neither of these changes are required if there is a dual stack proxy or CDN that sits infront of your application, as they will most likely talk to your application over IPv4.
The other gotcha is if you try to interrogate clientIP for analytics, authorization, geo-ip etc, which may need a little more care.
From your point of view it will "just work". One day you'll get an IPv6 address, if you haven't already, and it will look and feel identical to your IPv4 address. So I wouldn't worry about it.
(As a comcast customer that "one day" for me was several years ago)
