IPIP is a very simple method of tunneling IP packets over an IP connection.
- You need to have ip over ip routing support compiled in or compiled as a module
- Networking Options -> IP Tunneling (CONFIG_NET_IPIP)
You will also need /sbin/ip (see iproute(8)?). This usually comes in a package called iproute (eg Debian) or iproute2 depending on your distribution.