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.