====== IPv6 Privacy Extensions ======

Privacy Extensions as defined in [[http://tools.ietf.org/rfc/rfc4941.txt|RFC4941]] make your device change its IP every now and then. In Ubuntu, these privacy addresses are not enabled by default. Their generation is activated via the ''sysctl'' directive ''use_tempaddr'' that can be set to one of the following values:

  * ''0'' Don’t use privacy extensions.
  * ''1'' Generate privacy addresses
  * ''2'' Prefer privacy addresses and use them over the normal addresses.

You can activate privacy addresses in Ubuntu in one of two ways. You can enable it permanently by adding ''net.ipv6.conf.all.use_tempaddr=2'' to ''/etc/sysctl.conf''. Or enable it temporaily which will be reset on reboot:

<code bash>
echo 2 >/proc/sys/net/ipv6/conf/all/use_tempaddr
</code>

You can replace ''all'' with ''eth0'' to set the value for a particular network interface.