IPv6 used to be loaded as a module prior to jaunty but is now part of the kernel (probably since somewhere in 2.6.28), so disabling it via /etc/modprobe.d/aliases doesn’t work anymore. To check if IPv6 is disabled:
0 means IPv6 is enabled; 1 means disabled. So to disable:
echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
Reboot and good to go!
Nope it doesn’t work. Thanks to the heads up by jimmyjava, I proceed to verify and ipv6 continues its business as usual, regardless of /proc/sys/net/ipv6/conf/all/disable_ipv6. Gonna sit out and wait for some (kernel) updates for now…