IPv6: IPv6-in-IPv4 tunnel (SIT driver)

modulename: sit.ko

configname: CONFIG_IPV6_SIT

Linux Kernel Configuration
└─>Networking
└─>Networking options
└─>IPv6: IPv6-in-IPv4 tunnel (SIT driver)
In linux kernel since version 2.6.19 (release Date: 2006-11-29)  
Tunneling means encapsulating data of one protocol type within
another protocol and sending it over a channel that understands the
encapsulating protocol. This driver implements encapsulation of IPv6
into IPv4 packets. This is useful if you want to connect two IPv6
networks over an IPv4-only path.

Saying M here will produce a module called sit.ko. If unsure, say Y.

source code: