What is 6to4?

What is 6to4?

• A. IPv6 over IPv4 tunnels
• B. IPv4 over IPv6 tunnels
• C. IPv6 over MPLS
• D. IPv6 over UDP

Answer: (A)

6to4 is a way to carry IPv6 traffic over an IPv4 network by encapsulating IPv6 packets inside IPv4 datagrams (protocol 41). This lets IPv6 hosts communicate across IPv4 infrastructure without needing a native IPv6 path, using automatic tunneling. The IPv6 address format for 6to4 includes the 2002::/16 prefix, with the embedded IPv4 address identifying the tunnel endpoint, so the route can be determined without manual configuration. If a direct path isn’t available, relays help reach the IPv6 Internet. This description fits IPv6 over IPv4 tunnels. Other options describe different approaches: IPv4 over IPv6 tunnels, IPv6 over MPLS, or IPv6 over UDP, which are not what 6to4 defines.

6to4 is a way to carry IPv6 traffic over an IPv4 network by encapsulating IPv6 packets inside IPv4 datagrams (protocol 41). This lets IPv6 hosts communicate across IPv4 infrastructure without needing a native IPv6 path, using automatic tunneling. The IPv6 address format for 6to4 includes the 2002::/16 prefix, with the embedded IPv4 address identifying the tunnel endpoint, so the route can be determined without manual configuration. If a direct path isn’t available, relays help reach the IPv6 Internet. This description fits IPv6 over IPv4 tunnels. Other options describe different approaches: IPv4 over IPv6 tunnels, IPv6 over MPLS, or IPv6 over UDP, which are not what 6to4 defines.