The main development branch of NetworkManager has added the implementation of CLAT – a component of the 464XLAT technology (RFC 6877), which enables applications that only understand IPv4 to operate in networks that function exclusively on IPv6.
CLAT itself cannot work independently. It requires a NAT64 gateway (which can be on the provider's side, on the internet, or even on your home router). Overall, for most applications on modern operating systems, using DNS64 together with NAT64 is sufficient. However, some applications refuse to work if the device does not have a functioning IPv4 address. This occurs either due to the use of outdated networking methods or the use of IPv4 literals (specifying IPv4 directly, e.g., when searching for peers by IPv4 address). This is precisely the problem that CLAT addresses. A virtual IPv4 interface is created on the device, and all traffic from it is translated and sent to the NAT64 gateway.
Thanks to the use of CLAT on the device, it can operate in a network that only uses the IPv6 protocol without any restrictions on accessing IPv4 resources. A similar mechanism has long been available in all modern mobile operating systems, for instance, in Android starting from version 4.3 (2013), and in iOS, this happened in 12 (2018). Currently, desktop operating systems have been lagging behind. Full support is only available in macOS starting from Ventura (13), which was released in 2022. For Linux, it was necessary to install additional packages (such as clatd) to enable such functionality. CLAT support in Windows was also only available for WWAN connections, however, in December 2025, Microsoft began testing its own implementation of CLAT for all types of connections for Windows 11 users.
To use CLAT in NetworkManager today, you will need to install the test version 1.57. For example, users of the Fedora distribution can install the package NetworkManager from COPR with daily builds of the main branch of the project. Currently, automatic activation of CLAT is disabled, and it must be enabled manually using the option ipv4.clat=yes (later, after testing, it is planned to enable CLAT by default automatically).
This functionality is planned to be added in version 1.58 of NetworkManager. The current version is 1.54. Judging by the release cycle, version 1.56 is expected in the coming months, while 1.58 is slated for release closer to the end of 2026.
Source: linux.org.ru
