| Exam 400-101 | Question id=1656 | VPN Technologies |
Which two statements about IPv6 6to4 tunnels are true?
| A. |
They are point-to-multipoint tunnels. | |
| B. |
Sites use addresses from link-local scope. | |
| C. |
Sites use addresses from the 2002::/16 prefix. | |
| D. |
They are point-to-point tunnels. | |
| E. |
They rely on GRE encapsulation. |
6to4 is an Internet transition mechanism for migrating from Internet Protocol version 4 (IPv4) to version 6 (IPv6), a system that allows IPv6 packets to be transmitted over an IPv4 network (generally the IPv4 Internet) without the need to configure explicit tunnels. Special relay servers are also in place that allow 6to4 networks to communicate with native IPv6 networks.
For any 32-bit global IPv4 address that is assigned to a host, a 48-bit 6to4 IPv6 prefix can be constructed for use by that host by appending the IPv4 address to 2002::/16.