Comment 2 for bug 176125

I too think this should be the default policy, there is no good reason to expose your MAC-address to the world.
But adding net.ipv6.conf.all.use_tempaddr=2 to /etc/sysctl.conf was not enough to get it working on my Ethernet interface from boot.
I also had to add net.ipv6.conf.default.use_tempaddr=2, and force ipv6 to load before before sysctrl using /etc/modules.
Perhaps the default should be changed in the kernel instead?