IPv4 with CGNAT creates problems, not only for all IP address-based security mechanisms (e.g. blacklisting/whitelisting and reputation management), but also for law enforcement agencies. Back in 2017, for example, Europol reported that access providers using CGNAT were often no longer able to meet their legal obligation to provide details of the account holder linked to a given connection. As a result, the agency said, it was common for investigations to involve examining and tapping the connections of many more people than really necessary.

At about the same time, the European Commission published a letter describing how the EU planned to promote the adoption of IPv6. The ultimate aim being to have one user per IP address, thus facilitating the accurate targeting of investigative activities by the police and security services. The Commission plans to pursue that aim through procurement policy, research and project funding, and covenants.

The need for IPv6 is greater than ever due to unprecedented Internet growth and the rapid, continual development of smart phones, tablet computers and other online-enabled devices. In February 2011, the Internet Assigned Numbers Authority (IANA), the organization responsible for international IP address allocation, confirmed complete IPv4 resources depletion. Other global organizations have also reported critical limits on IPv4 address availability. In April 2011, the Asia Pacific Regional Internet Registry became the first of the IANA’s five regional registries to reach its IPv4 address limit. The American Registry for Internet Numbers (ARIN) is expected to follow suit in the near future.

Here's the point of the whole thing. The IETF people, when they were thinking about IPv6, saw this mess getting made - and maybe predicted some of the additional mess that would happen, though I doubt they could have predicted SDN and wifi repeater modes - and they said, hey wait a minute, stop right there. We don't need any of this crap! What if instead the world worked like this?

RT @Cyberprotect: Single #IPv6 packet KILLS Kaspersky-protected PCs, fix emerges http://t.co/tfLiJ2vQ3a #fb

Im IPv6-Netz der deutschen Bundeswehr wird es keine Network Address Translation (NAT) geben