Enabling IPv6-only Network Internet Access via NAT64

The core challenge in this scenario is bridging the gap between an IPv6-only internal network and the broader internet, which currently relies heavily on IPv4 infrastructure for many legacy servers. Because the internal network utilizes only IPv6 addressing, its clients cannot natively communicate with IPv4-only destination addresses without a translation mechanism.

While Static routing (D) is essential for directing traffic within a network or to a gateway, it does not perform protocol translation. A static route simply tells the router where to send packets; it does not change the IP version of those packets. Similarly, MPLS (A) is a carrier-grade technology for efficient packet switching across service provider networks and does not inherently solve IPv6-to-IPv4 compatibility issues for end-user connectivity. GRE (C), often cited by those favoring tunneling, creates a virtual point-to-point link but typically encapsulates one IP version inside another without translating the payload's addressing scheme for general internet access to mixed environments.

NAT64 (B) is the correct solution because it specifically functions as a transition technology that translates IPv6 packets to IPv4 packets (and vice versa). This allows IPv6-only internal clients to seamlessly connect to IPv4-only servers on the internet. By enabling NAT64 at the network boundary, the organization ensures that requests from modern IPv6 hosts are converted into IPv4 format before traversing the IPv4-centric parts of the internet, fulfilling the requirement for global connectivity.

The common trap here is focusing on connectivity methods like routing or tunneling while ignoring the fundamental address mismatch. The question explicitly states "IPv6 ONLY" internally, making translation mandatory rather than just routing.