blog.crox.net

Despite having read the opposite, it looks like IPv6 is disabled by default on the latest OSMC release (2015.06-1). I've tried adding a sysctl.d file to set /proc/sys/net/ipv6/conf/eth0/disable_ipv6 to 0, but this did not help. It worked only when I ran the command manually. By going through numerous forum posts I eventually found out that you need to use the connmanctl CLI tool:

root@osmc:~# connmanctl
connmanctl> services
*AO Wired                ethernet_b827ebaabbcc_cable
connmanctl> config ethernet_b827ebaabbcc_cable --ipv6 auto preferred
connmanctl> quit
root@osmc:~# 

This enables IPv6 with autoconfiguration, turns on Privacy Extensions and prefers these ephemeral addresses over the autoconfigured ones.

The same command works for wireless as well, you just need to select the appropriate interface (the service name will start with wifi_).

"help" will display basic usage info.

If for some reason you would like to disable IPv6, the command would be "config ... --ipv6 off".