6to4 Tunnels Over IPv4 Networks

To better enable the transition from IPv4 to IPv6, the Solaris operating system now supports the 6to4 transition mechanism. This mechanism enables the tunneling of packets from an isolated 6to4 IPv6 site across IPv4 networks to another isolated IPv6 site. 6to4 enables you to use one global IPv4 address and derive a complete 48-bit IPv6 global prefix for your site. To obtain technical information about 6to4 routing, refer to RFC 3056, "Connection of IPv6 Domains via IPv4 Clouds".

Consider implementing 6to4 if either or both of the following conditions exist at your IPv6 site:

• Your IPv6 site does not have an IPv6 connection to the Internet.

• Your isolated IPv6 site needs to communicate with another isolated IPv6 site

In the past, isolated IPv6 sites could not communicate with other IPv6 sites. 6to4 routing enables the isolated sites to transfer packets through a tunnel over an IPv4 network. The only requirement is a boundary router with a globally unique IPv4 address for the interface that connects to the IPv4 network.

You can configure more than one interface on a router for 6to4 support, provided that the interface meets the previously mentioned requirements. You do not need to manually configure hosts for 6to4 support. On receipt of a prefix advertisement from the 6to4 router, an IPv6 host automatically reconfigures an IPv6 interface with a 6to4 address.

The router encapsulates outbound IPv6 packets in an IPv4 header. An automatic tunnel is then constructed between the 6to4 router and the destination 6to4 site, over an IPv4 network. On receipt, the remote 6to4 router decapsulates the packets. The remote 6to4 router delivers the now standard IPv6 packets to the appropriate IPv6 nodes.

The 6to4 router can also tunnel packets to a native IPv6, non-6to4 site. In this instance, the 6to4 router sets up a tunnel over an IPv4 network to a 6to4 relay router. The relay router forwards the packets to an IPv6 network.

For More Information About 6to4 Routing

Configuring 6to4 routing is a straightforward task. The next table shows where to go for 6to4 configuration tasks and technical details.