[talent_deprived]

The biggest issue is IPv6 is a privacy, wide open wild west, there is no privacy on IPv6. Every device's IP is literally public, on the public Internet, 24/7. All so called privacy extensions or improvements do not change the lack of privacy of IPv6 and one more thing, the address structure sucks.

[10000truths]

This is wrong. Every IPv6 interface has a link-local address (which is not routable outside the LAN) as well as a global address. Global addresses are just addresses that come from a block allocated by the IANA. It has no bearing on whether the interface is reachable from the public internet. Just like with IPv4 networks, a stateful firewall will prevent unsolicited inbound connections.

[tremon]

Why is it wrong? You don't seem to be engaging the parent's point at all, which is that IPv6 addresses are a more specific identifier than current IPv4 addresses. The existence of link-local addressing has no bearing on that argument, because those addresses are non-routable by definition. Nor does stateful firewalling prevent your unique device address from being broadcast over the Internet, you'd need 6-to-6 NAT to achieve that.

[KaiserPro]

Every Ipv4 device has a loopback (well most do.) thats not what they are on about.

Having NAT and a firewall gives you a better illusion of privacy. Sure you can track devices from the outside world, but its pretty hard.

If you have v6 configured in a certain way, then your IP address is basically a UUID for your machine. Plus you can't really just stop ICMP anymore so you can trivially ping it (caveats apply)

[LinuxBender]

FWIW this does not have to be true for companies that do not wish to expose internal nodes. I'm not even talking about the privacy extensions. I realize that people beat the drums that one must not NAT IPv6 but it can absolutely be a NAT just like IPv4. I would actually expect in most companies that they don't even add IPv6 inside their datacenters, rather they just put a block of IPv6 addresses on some load balancers at the edge and then point their edge devices L4 and L7 mapping to IPv4 nodes in their datacenter. The same could apply to VPN/WAN configurations in some cases much like how mobile networks are configured nowadays. There would need to be some of this regardless due to ACL's required between companies that don't use network VPN's for restricted end-points. e.g. PCI to PCI environments.

In the early days of IPv4 many big companies did not NAT IPv4. I was at a company that did this. Our workstations all had routable public IPv4 addresses. There are still some companies that do this. One of these was a company that had 20 managers and VP's on a call when I just wanted to give their network engineer a CIDR block and a pre-shared secret for a network VPN. I suspect they will be using public IPv4 addresses internally forever. And I doubt they will ever sell their /8's unless people comment on their Vogon poetry.

Amazon is probably one of the exceptions as they have so many geographically disperse configurations it would be harder to continue using RFC1918 address space. Not impossible, just difficult. I can think of a few other big companies that do manufacturing that are spread out around the world that would probably run into walls with RFC1918 at some point. I've seen some of them take over public address space for internal routing which then breaks access to some things on the internet thus requiring double/triple NATs. 1/8 assorted, 25/8 MoD, 26/8 DISA are a few I've seen.

[SoftTalker]

> In the early days of IPv4 many big companies did not NAT IPv4. I was at a company that did this. Our workstations all had routable public IPv4 addresses.

A lot of big universities did this and even still do this to a large degree. They got huge IPv4 allocations early and there was no scarcity.

[icedchai]

All of the early Internet companies I worked at were like that, up until roughly 2000: public IPs direct on the desktop. My 90's home network was also like that. I had a /24 block from the old class C "swamp" space. I still have it, actually. It's legacy space, no ARIN fees.

[taway1237]

In my current company (related to academic institution that introduced internet to my country) every office workstation has FOUR public (but firewalled of course) IPv4 addresses. And every user has an unique VPN IPv4 address on top of that.

[talent_deprived]

I remember the days of non-NAT IPv4, though I'd forgotten until you mentioned it. I'd be OK with NAT IPv6, though the addresses are still ugly and difficult to reason about.

[p1mrx]

CIDR IP addresses are based on binary number prefixes. If you think it's easier to reason about them in decimal than hex, then you probably don't really understand binary.

[icedchai]

IP-based "privacy" is an illusion. With IPv4, your public IP (NAT router IP address) may not change for months, years, and possibly not until your change your router/MAC address. With IPv6 privacy extensions, your address changes regularly. This seems like an improvement.

[ninkendo]

> With IPv6 privacy extensions, your address changes regularly. This seems like an improvement.

Eh… If I was a company that wanted to use IP addresses to fingerprint users, IPv4 vs IPv6+privacy extensions both seem identical to me. Multiple requests from the same IPv4 address mean “someone, perhaps more than one person, from the same household/wifi”. Whereas multiple IPv6+privacy requests from the same /64 prefix means the same thing.

ie. You just consider the first 64 bits of the IP and can assume the same amount of information you already would assume from the IPv4 address. Just ignore the trailing 64 bits because it’s expected that they’ll be randomized/shuffled even from the same client.

[talent_deprived]

The IPv4 at my router yes. That's where tracking ends. IPv6 privacy is an illusion, try the test I described, remove IPv6 from your router at home, wait a few hours or few days, the family will complain search results are odd or messed up and that's only the beginning of it.

I don't know how companies are doing it but they are able to track your IPv6 changed daily or not.

[icedchai]

They probably just track the IPv6 /64. With prefix delegation, the /64 would rarely change, unless your provider delegated a new block. This is similar to your IPv4 router changing its address w/DHCP: it happens, but is relatively rare.

[Thiez]

Also just cookies and browser fingerprinting.