As a part of the IPv4 to IPv6 transition, IPv6 specifies methods for encapsulating IPv6 packets within IPv4 packets. IPv6 also specifies IPv6 packets that are encapsulated within IPv6 packets. Consequently, a new module, tun(7M), which performs the actual packet encapsulation, has been added. This module, which is known as the tunneling module, is plumbed and is configured by using the ifconfig utility the same as any physical interface. This module enables the tunneling module to be pushed between IP device and IP module. Tunneling devices also have entries in the system interface list.
The ifconfig(1M) utility is also modified. You use this utility to create the IPv6 stack. This utility also supports new parameters that are described in this chapter.
The in.ndpd(1M) daemon is added to perform router discovery and stateless address autoconfiguration.