464XLAT
464XLAT, defined in RFC 6877, lets an IPv4-only application keep working on a network that only assigns IPv6 addresses, by combining two translators: a CLAT (customer-side translator) running on the device itself, and a PLAT (provider-side translator) -- typically a NAT64 gateway -- run by the network operator. The CLAT translates an app's outgoing IPv4 traffic into IPv6 locally, the PLAT translates it back to IPv4 at the network edge to reach the IPv4 internet, and replies retrace the same path in reverse. This solves a gap that NAT64 and DNS64 alone leave open: DNS64 only works when an app does a DNS lookup and gets a synthesized address back, but some apps connect to a hardcoded IPv4 literal address or skip DNS entirely, giving DNS64 no hostname to synthesize an answer for. The CLAT intercepts that traffic before it ever reaches DNS. 464XLAT is widely used on mobile networks and has shipped as a built-in CLAT in Android since version 4.3, letting carriers run IPv6-only radio networks while still supporting IPv4-only apps and websites without every app needing its own IPv6 support.
By AdminKit team, Netbase JSC · Updated