In this section we'll talk about configuring some of the transition mechanisms. We'll give more complete descriptions for the more common ones (configured tunnels and 6to4) that are widely used to provide connectivity before native IPv6 is available.
Configured tunnels are normally used to encapsulate IPv6 in IPv4 and ship it from one point in the Internet to another. To configure a tunnel of this sort you usually need 4 pieces of information: the source and destination IPv4 addresses used for encapsulation, and the source and destination IPv6 addresses assigned to either end of the virtual, point-to-point link.
The exact mechanism used to create tunnels varies a bit from platform to platform. On some platforms, the tunnel is presented as a point-to-point interface, but on others, the tunnel is created by setting the next hop to be an IPv4 compatible IPv6 address. Table 5-13 and Table 5-14 show the steps for boot-time and run-time configuration of tunnels on our selected operating systems.
Table 5-13. Boot time configuration of IPv6 over IPv4 tunnel
Enabling a configured tunnel at boot
Create /etc/hostname6.ip.tun0 containing the following:
Create a /etc/sysconfig/network-scripts/ifcfg-sit
Use smit to ...