Which IPv6 transition technology is designed to provide IPv6 connectivity for hosts behind NAT without requiring native IPv6?

Which IPv6 transition technology is designed to provide IPv6 connectivity for hosts behind NAT without requiring native IPv6?

• A. NAT64
• B. Dual Stack
• C. 6to4
• D. Teredo

Answer: (D)

Providing IPv6 connectivity for a device that sits behind an IPv4 NAT without needing native IPv6 on the network relies on a NAT-traversal approach. Teredo is designed for this exact scenario: it tunnels IPv6 over UDP across an IPv4 network, allowing a host behind a NAT to reach IPv6 destinations without requiring a native IPv6 path. It negotiates with Teredo servers and uses relays to reach the IPv6 Internet, so the local network can stay IPv4-only while still getting IPv6 connectivity. In contrast, the other options don’t match this situation as well. Dual stack requires native IPv6 on the network. 6to4 depends on a routable IPv4 address and doesn’t handle NATs reliably. NAT64 enables IPv6-only networks to reach IPv4 resources, not to provide IPv6 connectivity to a host behind NAT in an IPv4 world.

Providing IPv6 connectivity for a device that sits behind an IPv4 NAT without needing native IPv6 on the network relies on a NAT-traversal approach. Teredo is designed for this exact scenario: it tunnels IPv6 over UDP across an IPv4 network, allowing a host behind a NAT to reach IPv6 destinations without requiring a native IPv6 path. It negotiates with Teredo servers and uses relays to reach the IPv6 Internet, so the local network can stay IPv4-only while still getting IPv6 connectivity.

In contrast, the other options don’t match this situation as well. Dual stack requires native IPv6 on the network. 6to4 depends on a routable IPv4 address and doesn’t handle NATs reliably. NAT64 enables IPv6-only networks to reach IPv4 resources, not to provide IPv6 connectivity to a host behind NAT in an IPv4 world.