That's a little silly, IPv6 privacy addresses are functionally infinite and unless you have a truly huge network behind that NAT then it's not hard to reduce the list of candidates if you have any other information at all.

The V6 privacy addresses are typically only rotated daily but the space is so large that it could be done almost per connection of the stack and router could handle that. Realistic rotation limits are probably every few minutes.

Nearly all modern operating systems use the IPv6 privacy extension, which creates random addresses periodically. Thus the tracking is randomized to the /64 (which is an end customer). This is more or less the same as with IPv4 (without CGNAT)

Is a /64 really an end customer? How common is that?

Both of my ISPs hand out new ISPs hand out new /64 prefixes every so often. One does it every half-hour, the other is comparable but I don't remember. I think they do it to encourage business customers to get more expensive connections, but the effect on my connections is that each device's IP address changes every few minutes, within the ISP's /32, and doesn't repeat in a year... and I do wonder how many IPSs do this.

/64 is a subnet. End customers get /56 to /48 so that they can run multiple subnets. It is, unfortunately, more common than it should be for ISPs to not even give the minimum of that range though.

Changing your prefix every half an hour would be... unusual, at least, although again I wouldn't put it past some ISPs to do that (possibly unintentionally)... but sounds like your prefix might be changing every time you do a DHCPv6-PD request, which makes me wonder if your DHCPv6 client might be generating a new DUID for every request rather than remembering it.

It's a subnet, yes. GP declared it to be approximately the same as an end customer.

How do you know that the ISP replacing it often is "unusual, to say the least"? Or is that something you know?

There's a fair few ISPs changing the prefix every day, but this is the first I've heard of anyone changing it every half an hour. If it was common I would've heard a lot of complaining about it by now.

Would you? You haven't heard any complaint from me, and I'm a unix greybeard with a home network and lots of incoming IPv6 connections — all I needed to do was shrink my DNS TTLs, and everything works well. Software's grown resilient to IP address changes nowadays.

Even my incoming rdiff-backup jobs don't raise a noticeable number of errors.

I read most reddit posts that mention IPv6, as well as comments on any blog post, news story etc that makes the rounds. People bitch and moan about every little problem with v6, including blaming it for problems caused by v4 or by completely unrelated causes and with no regard for whether the problem has been fixed 20 years ago or was just imaginary in the first place. They'll even complain about the benefits it gets them.

If 30-minutely prefix changes were common, people would definitely be complaining about it.

...but okay, I won't claim that I catch everything. Can I ask which ISP this is, or at least which country? Perhaps it's common in places that don't have much presence in the English-speaking parts of the internet.

It's nice to hear that it mostly works for you. It should do, but a lot of software is terrible at handling dynamic changes -- it seems to be something that programmers struggle with. The biggest problem should be that long-running connections aren't possible.

my residential isp hands out as many /48s as you want

Irrelevant. It's within your subnet, and it's nowhere near 32b.

https://www.transtutors.com/questions/how-many-bits-are-need...

Your subnet is no more uniquely identifying than a (non-CGNAT) IPv4 address; if 32 bits identifies which router you're using (whether that's your home, coffee shop or whatever) then a 64 bit identifier doesn't make that router any more identified.

In the typical IPv4 setup, your network gets an IPv4 address. Everything in your network is trivial to group.

In the typical IPv6 setup, your network gets an IPv6 prefix from which client devices use randomized and rotating IPs. Everything in your network is trivial to group.

How long the network-identifying address/prefix is stable is purely an ISP design choice - some keep them as long as possible, others force a change regularly.

yeah, like when you have a /32 IPv4 dedicated to your private subnet; it's the same.

Why use IPv6 if you are going to hand out IPv4 addresses?

People know why. Even if a few really get 32's, it's PR. The endgame is the same.

This is a critical path item for removing the ability to have 2 party value transfers. The power at stake is incalculably valuable.

What do you mean by " Even if a few really get 32's, it's PR."?

The vast majority of IPv4 connections get an IPv4 IP (= a /32), CGNAT is pretty much only used by providers that don't have another choice and has various downsides for users too.

Obviously, it's temporary. Handing every possible IPv4 user 2^32 IPv6 addresses is a worse than pointless gesture. It's an 10^9 scale changing of the subject.

IPv4 not having enough addresses is why it's valuable. It's impossible to arm band every human with 32b.

EDIT: I'm comment limited for the night. @efzx: Seeing "google" in the same sentience with "does not have anything with tracking" is pretty good stuff.

Not just tagging many ISPs especially FTTH/P don’t randomize IPv6 addresses so all the IP addresses in your town, neighborhood and even building share the same prefixes and they are hierarchical so by just knowing your IP address one could figure out where you live.

Network-wise this is a feature. Having the address space reflect network layout allows for vastly simpler, thus more efficient, routing tables.

I understand that even without efficiencies in routing it makes senses from an operational perspective it doesn’t mean that the privacy implications are quite horrendous.

Oh the poor SRAM on those ASIC's.

> Apple tells app devs to use IPv6 as it's 1.4 times faster than IPv4

Do you have better insight than Apple?

The faster excuse. yawn Bandwidth (aka time waiting) is like a gas, it expands to fill all available human tolerance.

It's also always there to pretend the major corps care about (insert 15s ad here) it.

If you really measure response time, frame by frame, Windows 3.1 is faster than Windows Billion.

Process improvements in hardware obviate any trivial 40% benchmark. 400%, maybe, lets talk about it.

It's utterly irrelevant compared to what being to tag every item every person ever comes into contact with and the interactions of those items with other items; iterated as many times as desired.

Hardly a prerequisite; a lot of people manage to track individuals using cookies (and many other browser-related things). AFAICT the companies that advertise tracking solutions don't mention IP addresses very much.

It feels like Google has a dog in this fight.

Why can't Android devices connect to ipv4-only networks?

Of course they can, the majority of networks are IPv4 only.

IPv6 still has NAT. There's public and private IPv6 addresses, same as IPv4.

Google building their infrastructure around IPv6 does not have anything with tracking IPv6 users

IPv6 doesn't have NAT, it has different addresses for global and local scopes, but your OS never translates between these addresses and it doesn't need to keep a table of translations & connections, as you'd have with IPv4 and NAT.

> IPv6 doesn't have NAT

This is widely believed, but it's false. There is nothing whatsoever stopping you doing NAT with IPv6, even though you probably don't need to.

Some use it because it simplifies load balancing if you're thinking network-design in an IPv4-way.

Technically you can do NAT with IPv6, just almost nobody ever does it for the reasons you specify. It's pointless to do NAT when there is no address shortage.

In the early to mid 90's, nobody did NAT with IPv4 either.

Network Prefix Translation or NPT is the equivalent of NAT in IPv6. Let's say you have six WANs (I do in the office) and each has its own IPv6 allocation and BGP and a personal allocation is not available.

Your client machines don't know what is going on at the border, so they can't "choose" a route out unless you turn the lot into routers and use OSPF or something internally.

So NPT. Your router sends flows out over links and rewrites the prefix accordingly for that link. Its a bit horrible and I've decided not to bother yet.

Typically "your OS" doesn't do NAT in IPv4, unless your using a NAT router as your end user device.

And surely you can do NAT with IPv6, Google for NAT66, but your average Linux box can do it. It's just almost never needed.