How to enable / disable privacy addressing for IPv6 in Linux

Per this documentation, there is a kernel setting for use of RFC3041 IPv6 "privacy addressing" in Linux. It seems to be enabled by default on Ubuntu 12.04: which is fine for general users, but not desirable for administrative purposes.

To disable privacy addressing, add the following to /etc/sysctl.conf , then restart the system...

net.ipv6.conf.all.use_tempaddr=0
net.ipv6.conf.default.use_tempaddr=0

To enable (or restore Ubuntu 12.04 default)...

net.ipv6.conf.all.use_tempaddr=2
net.ipv6.conf.default.use_tempaddr=2