The year of IPv6-only desktop#

Ondřej Caletka, RIPE NCC

• Why: Marks the moment IPv6-only operation crosses from mobile networks to desktops — macOS already opts out of IPv4 on IPv6-mostly networks, Windows 11 has it in preview, and NetworkManager on Linux supports it.
• What: The "IPv6-mostly" model: the network signals NAT64 support via DHCPv4 option 108, and devices with CLAT (or enforced IPv6 compatibility) autonomously opt out of IPv4. Framed by the RIPE meeting network's own decade-long journey (failed experiment in 2013 → working IPv6-mostly main network today), and the argument that dual stack failed as a transition mechanism: double the work, with IPv6 problems masked by the IPv4 safety net.
• How: NAT64 won because it's the one-box solution the industry actually chose; CLAT handles IPv4-only applications on the client. Practical pitfalls called out: IPv4-only VPNs with IPv6 killswitch features, and devices opting out even when they shouldn't.
• Where applicable: Enterprise/access network design; the WinCLAT arrival makes IPv6-only enterprise LANs genuinely deployable, which will change DC and edge design assumptions.